Constant acceleration Definition and 340 Threads

Homework Statement Al and Bert are jogging side by side on a trail in the woods at a speed of 0.75 m/s. Suddenly, Al sees the end of the trail 35 m ahead and decides to speed up to reach it. He accelerates at constant rate of 50 m/(s^2) while Bert continues on at a constant speed. (a) How...

i was having a discussion with a friend recently and he seemed to think that you cannot accelerate to a speed which is faster than the speed of the accelerating force coming out of the back of the rocket. but i thought it was the case that u could get to very high speeds in space even if you...

Homework Statement A stolen car,travelling at constant speed of 40m/s,passes a police car in a lay-by.The police car sets off three seconds later,accelerating uniformly at 8m/s^2.How long does the car take to intercept the stolen car and how far from the lay-by does this happen?

1. A car rolls down such an incline from rest, starting at different positions on the incline. If the car coasts distances of .7430036cm, .9169641cm, 2.025999cm, and 1.61088cm, starting from rest each time and requires respective times of 3.5 sec, 7 sec, 7.25 sec, and 7.75 sec, is there...

Tired and not understanding Calculus. So, velocity equals dx/dt and acceleration is dv/dt But to derive the constant acceleration equations, my professor took the integral of vdt = dx, which we got from v = dx/dt. I follow all of the math that comes after that, but I don't understand...

Homework Statement According to the Guinness Book of World Records, the longest home run ever measured was hit by Roy “Dizzy” Carlyle in a minor league game. The ball traveled 188 m before landing on the ground outside the ballpark. Assuming the ball's initial velocity was 56 degrees above...

Hi, I hope it is a very simple mistake and easy to spot. Suppose you start at rest so initial velocity is 0 and you accelerate constantly over a certain distance. An acceleration vs. distance graph (not time) would be like a rectangle. The area under the graph would be A=as=(s/t2)*s = v2...

Homework Statement This is actually related to another https://www.physicsforums.com/showthread.php?t=531596" basically, I have a Constance force of gravity, and a non constant force of a rocket going the opposite way. the net force would be something like F(booster) -Force(gravity)...

Homework Statement A mouse leaves a hole in the baseboard and runs along the wall in a straight line towards a cupboard where cookies are stored, 12 meters from the hole. The mouse starts at rest and maintains a constant acceleration of 0.1m/s2 before reaching top speed of 1 m/s, which it...

Homework Statement A sports car accelerates in third gear from 48.3 km/h to 80.5 hm/h in 3.7 seconds. (a)What is the average acceleration of this car in m/s^2? (b) If the car maintained this acceleration, how fast would it be moving one second later? Homework Equations a= dv/dt 1km =...

Homework Statement An entertainer juggles balls while doing other activities. In one act, she throws a ball vertically upward, and while it is in the air, she runs to and from a table 5.80 m away at a constant speed of 2.40 m/s, returning just in time to catch the falling ball. 1. With what...

Homework Statement painter is standing on scaffolding that is raised at constant speed. As he travels upward, he accidentally nudges a paint can off the scaffolding and it falls a distance 16.0 m to the ground. You are watching, and measure with your stopwatch that it takes a time of 3.26 s...

You are driving down the highway late one night at 20 \rm m/s when a deer steps onto the road 35 m in front of you. Your reaction time before stepping on the brakes is 0.50 s , and the maximum deceleration of your car is 10 m/s^2 . How much distance is between you and the deer when you come to a...

Homework Statement A hot air ballonist rising verticlly at a constant velocity "vb", releases a sandbag at the instant the sandbag is "h" meters above the ground. Given [vb,h] Determine: a. The time for the sandbag to hit the ground b. The speed of the sandbag just before hitting the...

A "rocket car" is launched along a long straight track at t=0s. It moves with constant acceleration a1=1.2m/s2. At t=2s a second car is launched with constant acceleration a2=7.2m/s2. At what time does the second car catch up with the first? How far down the track do they meet? I...

I'm trying to understand the math that leads to the derived equations cause I can't seem to derived them my self. All the videos / tutorials online just show the equation it derived from and then the derived equation it self, I was more interested in the mechanics cause I was told I would have...

Homework Statement At the instant the traffic light turns greeen, Stan Speedy starts from rest and accelerates at "a". At the same instant Kathy Kool starts from rest "d" behind Stan and accelerates at "5/4a" (not sure, but I think this is meant to be (5/4)a or 5a/4, my attempts with "5/4a"...

Homework Statement You drop a stone down into a well to find the depth of the well. You hear the sound of the splash 3.5 s after you let the stone go. Homework Equations s(displacement)=v_0t \cdot \frac 12 at^2 The Attempt at a Solution I have t_{total}=3.5 s Stone...

Homework Statement A rocket is fired vertically and contiues for 1 minute with the acceleration 20 m/s^2. Then it has used up all the fuel , and the rocket continues in free fall. a) How high does the rocket come? Homework Equations s(displacement)=v_0t + \frac 12 at^2 The...

1. A car sits on a freeway entrance ramp waiting for a break in traffic. The driver sees a gap and accelerates onto the freeway. Thar car starts from rest and moves in a straight line and has a speed of 20m/s when it reaches the end of the 120 m long ramp. Find A] acceleration of the car. B]...

The human body can survive an acceleration trauma incident (sudden stop) if the magnitude of the acceleration is less than 250 m/s2. If you are in an automobile accident with an initial speed of 150 km/h (65 mi/h) and you are stopped by an airbag that inflates from the dashboard, over what...

Homework Statement I am doing some study for a short sci-fi story I'm writing. I'm trying to figure out how to determine the time that a craft has traveled if I know the constant acceleration and distance traveled. eg. A ship accelerates constantly at 1g and travels 0.5 light years. How long...

Homework Statement A scaffolding is rising at 1.0 m/s when at a height of 50.0 m , then the man on the scaffolding drop a can. determine: a. the time needed for the can to reach the ground . b. what is the final velocity ?Homework Equations note: g=-9.8 m/s the letter o in the equation...

Homework Statement A particle moving at 5m/s reverses its direction in 1 s to move at 5m/s in the opposite direction. If its acceleration is constant, what distance does it travel? Homework Equations x=vot+0.5at^2; a=(vf-vi)/t The Attempt at a Solution total time is 1s therefore...

Homework Statement At the instant the traffic light turns green, an automobile starts with a constant acceleration a of 2.2 m/s2. At the same instant a truck, traveling with a constant speed of 8.6 m/s, overtakes and passes the automobile. (a) How far beyond the traffic signal will the...

Link to guy's blog post: http://ftlfactor.com/2011/04/23/how-does-special-relativity-allow-effectively-faster-than-light-travel/#comment-117 He says he has a PhD in space physics. My understanding of special relativity was that the speed of light is always constant no matter what...

Homework Statement Two cars, a red one(left side) and a green one(right side), are moving toward each other in adjacent lanes. At time t=0, the red car is at position x= 0 m and the green car is at position x= 220 m. If the the red car has a constant velocity of 20km/hr, it passes the green car...

Homework Statement A body has a constant acceleration of +5 ft/s^2, an initial speed of -10 ft/s, and a time travel of 4 seconds. A)Find the total distance covered B)Find the time at which the body has an instantaneous speed of zero Homework Equations speed=distance/time...

Can you please help me with instructing the difference between average and constant acceleration , and what is the most general that concludes the another ?

Homework Statement A body moving with constant acceleration in a straight line covers the distance between two points 60.0m apart in 5.0s. Its velocity as it passes the second point is 15.0m/s. a) What is: i) The acceleration of the object? ii) Its initial velocity? b)...

The barrel of a rifle has a length of 0.877 m. A bullet leaves the muzzle of a rifle with a speed of 612 m/s. What is the acceleration of the bullet while in the barrel? A bullet in a rifle barrel does not have constant acceleration, but constant acceleration is to be assumed for this problem...

Homework Statement The head of a woodpecker is moving forward at a speed of 7.49 m/s when the beak makes first contact with a tree limb. The beak stops after penetrating the limb by 1.87 mm. Assuming the acceleration to be constant, find the acceleration magnitude in terms of g. Know...

Homework Statement Hi. I've had some trouble solving this exercise, and I simply can't find the right solution. Hopefully you might help me out...? Here's the task: A plane (not airplane) has an inclination that allows a particle sliding on the slippery slope, and has an acceleration of 4.00...

Homework Statement A stone is thrown vertically upward. On its way up it passes point A with speed v and point B 3.0 m higher than point A.With speed (1/2)*v Calculate a. the speed v b. the maximum height reached by the stone above point B. Homework Equations v = v0 + at The Attempt...

Homework Statement You are arguing over a cell phone while trailing an unmarked police car by 25 m; both your car and the police car are traveling at 110 km/h. Your argument diverts your attention from the police car for 2.0 s. At the beginning of that 2.0 s, the police officer begins braking...

Homework Statement A diver jumps from a 10 m high diving board at an angle of 30 deg above horizontal. 2 seconds later the diver reaches water. What is the initial speed of the diver ? Homework Equations v = vi + at s = si + vit +0.5(a)t^2 v^2= Vi^2 + 2 a (s-s0) The Attempt at a...

Time dilation formula for accelerated circular and spherical motion A traveler goes in an accelerated circular motion of radius r from spacestation A to spacestation B with a constant proper acceleration alpha, e.g. there is also a tangential acceleration...

Homework Statement You're speeding at 85 km/h when you notice that you're only 10m behind the car in front of you, which is moving at the legal speed limit of 60 km/h. You slam on your brakes, and your car decelerates at 4.2 m/s^2. Assuming the car in front of you continues at constant...

Can Someone help me with this constant acceleration problem?! pleasez [b]1. A train which is moving with uniform acceleration is observed to take 20s and 30s, respectively, to travel successive 400m. How much farther will it travel vefore coming to rest if the acceleration remains constant...

Homework Statement A stone is projected horizontally from the top of a vertical sea cliff 49m high, with a speed of 20ms^-1. Neglecting air resistance, calculate: The time that it takes to reach the sea. Homework Equations v² =u²+2as t=v-u/a t=d/s The Attempt at a Solution...

Homework Statement Assume a particle moves along the x-axis. It is uniformly accelerated, in the sense that the acceleration measured in its instantaneous rest frame is always g, a constant. Find x and t as functions of the proper time tau if the particle is at x0 at t=0 with no velocity. The...

Homework Statement A cyclist starts at the top of a straight slope with an initial velocity of 3.00m/s. Five seconds later, she is at the bottom of the incline, having traveled 50.0m. Find her velocity at the bottom of the hill and her acceleration, assuming it to be constant. Homework...

Homework Statement An automobile moving along a straight track changes its velocity from 40 m/s to 80 m/s in a distance of 200 m. What is the (constant) acceleration component of the vehicle during this time? Homework Equations The Attempt at a Solution I try to solve this...

Homework Statement A pizza is being dropped from a height of 20 m. Another pizza is being thrown up at 30m/s from 0m(the one falling is above the one being thrown). At what position in the air will they meet? a= -10m/s^2 Homework Equations Im not sure but i think that some of the b5...

Homework Statement When a high-speed passenger train traveling at vP = 55 m/s rounds a bend, the engineer is shocked to see that a locomotive has improperly entered onto the track from a siding and is a distance D = 1000 m ahead). The locomotive is moving at vL = 12 m/s. The engineer of the...

Homework Statement A car is at a stop light, when the light turns green a truck blows through the intersection at 22 m/s, and remains constant. The car begins to accelerate (assume at the exact same time as the truck goes through intersection) at a rate of 3.55 m/s/s. A) How far away from...

Going Up An elevator cab in a New York hotel has a total run of 185 m. Its maximum speed is 261 m/min. Its acceleration (both speeding up and slowing down) has a magnitude of 1.21 m/s2. (1) How far does the cab move while accelerating to full speed from rest? v = 261m/min = 261m/min *...

Homework Statement An arrow is shot vertically upward with an initial speed of 25 m/s. Two seconds later, another arrow is shot upward with the same speed. On its way up, the second arrow meets the first arrow on its way down. Assume that both arrows experience a constant downward acceleration...

Homework Statement A pedestrian is running at his maximum speed of 6.0 m/s trying to catch a bus that is stopped at a traffic light. When he is at 16 m from the bus, the light changes and the bus pulls away from the pedestrian with an acceleration of 1.0 m/s2. Does the pedestrian catch the...

Homework Statement A truck travels at a constant speed of 28.0 m/s in the fast lane of a two-lane highway. It approaches a stationary car stopped a the side of the road. When the truck is still 125 m behind the car, the car pulls out into the slow lane with an acceleration of 2.6 m/s2. How...