How to Solve Basic Physics Problems Correctly?

[Ahmad786]

8. If the displacement of a car was 150 km [E] and the velocity was 50.0 km/h [E], what was
the time of travel?
A. 100 h [E]
B. 3.0 h
C. 100 h
D. 3.0 h [E]

(I divided 150 by 50)

9. The airport is 60.0 km away and you have 1.00 h to get there. If your speed for the first
40.0 minutes is 48.0 km/h, how fast must you travel in the remaining 20 minutes to get
there within the time?
A. 48.0 km/h
B. 84.0 km/h
C. 90.0 km/h
D. 180 km/h
( for this I converted the times to hours then I found the distance it traveled first then I subtracted it from the whole distance it has to travel then I divided the amount it still had to travel by the remaining time)

10. If the velocity of a car is 16 m/s and it travels for a time of 6.0 s, what is the
displacement? Express the displacement correctly.
A. 96 m
B. 10 m
C. 96 m
D. 10 m/s
(for this I multiplied the velocity by the time it traveled and inferred that it doesn't include direction)

11. A racoon travels from point A to point B in 11 s. If the racoon was displaced 55 m ,
what was its velocity? Express the number correctly.
A. 5.0 m/s
B. 5.0 m/s
C. 44 m/s
D. 66 m/s
(for this I divided the displacement by the time)

12. A car driver speeds up from 5.00 m/s [E] to 15.0 m/s [E] in 4.00 s. Determine the car’s
acceleration.
A. 40.0 m/s2 [E]
B. 40.0 m/s [E]
C. 2.50 m/s2 [E]
D. 2.50 m/s [E]
(for this I subtracted the final velocity from the initial velocity and the divided this value from the time)

13. An 1800 kg Volkswagen traveling at 60.0 km/h impacts into a concrete barrier and stops
in 0.420 s. The magnitude of the collision force on the automobile is
A. 2.57 x 10⁵ N
B. 7.14 x 10⁴ N
C. 1.26 x 10⁴ N
D. 1.08 x 10⁵ N
(for this I first converted the speed to m/s then divided this by the time to get acceleration then I multiplied this by 1800 Kg is this the correct way to do it do i calculate the acceleration by dividing the given velocityby the time or is there another way to do it)

 

[cronxeh]

All of the answers are correct

#13 :

impulse = mass*speed
speed = 16.67 m/s
mass= 1800 kg

force of collision = impulse/time

 

[kerimek]

Hello,

I would like to provide some clarifications and explanations for the questions and answers provided.

Firstly, for question 8, the correct answer is B. 3.0 h. This can be calculated by dividing the displacement (150 km) by the velocity (50 km/h), which gives us a time of 3 hours. The direction (E) is not relevant in this calculation as time is a scalar quantity.

For question 9, the correct answer is C. 90.0 km/h. The method used to solve this question is correct, but the final answer should be in km/h rather than just km.

For question 10, the correct answer is A. 96 m . The displacement is a vector quantity and should include the direction (S) in the answer. The method used to solve this question is correct.

For question 11, the correct answer is B. 5.0 m/s . Since the displacement and velocity are both in the same direction (S), the velocity will also be in the same direction. Therefore, the answer should include the direction (S). The method used to solve this question is correct.

For question 12, the correct answer is C. 2.50 m/s2 [E]. Acceleration is calculated by dividing the change in velocity by the time, not by subtracting final velocity from initial velocity. Therefore, the answer should be in m/s2. The method used to solve this question is correct.

For question 13, the correct answer is D. 1.08 x 105 N. To calculate the force, we need to use the formula F=ma, where m is the mass (1800 kg) and a is the acceleration. The acceleration can be calculated by dividing the change in velocity (60 km/h) by the time (0.420 s). However, please note that the speed should be converted to m/s before calculating the acceleration. The method used to solve this question is correct.

I hope this helps clarify the answers and methods used. It is important to pay attention to the units and direction when solving physics problems. Keep up the good work in checking your answers and understanding the concepts. Best of luck!