What Is the Car's Acceleration Given These Forces?

In summary, a 1200 kg car traveling at 50 km/h experiences a forward force of 7500 N from the wheels, while also experiencing air resistance of 5000 N and road friction of 2200 N. Using the formula a = ƩF/m, we can calculate the car's acceleration to be 0.250 m/s^2. However, in attempting to solve the problem, there was a mistake in interpreting the direction of the forces, which led to an incorrect answer. It is important to carefully review the key principles of forces to avoid such errors.
  • #1
harujina
77
1

Homework Statement



A 1200 kg car travels at 50 km/h and experiences air resistance of 5000 N and road friction of 2200 N. If the wheels push with a force of 7500 N, what is the car's acceleration?

Homework Equations



a = ƩF/m

The Attempt at a Solution



I got ƩF = 8590 N [E52°S] then plugged it into the equation,
but it did not work to the correct answer of 0.250m/s^2.

I'm thinking I probably had to make use of the 50 km/h variable somewhere, which I didn't.
When and where would that apply...?
 
Physics news on Phys.org
  • #2
harujina said:
I got ƩF = 8590 N [E52°S] then plugged it into the equation,
How did you find that sum? Realize that the forces point in different directions. Where did that angle come from?
 
  • #3
how did you get ƩF=8590 [E52°S]?

To me it seems you interpreted it wrong. Its a one dimensional problem, but by the looks of your answer it is a vector result.

car is being pushed forward by 7500 N...backwards by air resistance of 5000 N...again backwards by road friction of 2200 N.

ƩF=ma

try again you should arrive at the right answer.

P.S. - No offense, but please consider revising the key points of the chapter associated with Forces.

Edit : Doc Al got there first!
 
  • #4
ohh, okay i don't know why i thought air friction was in the direction north.
but thank you and yes, i just started this unit yesterday, i will make sure to revise!
 
  • #5
harujina said:
ohh, okay i don't know why i thought air friction was in the direction north.
but thank you and yes, i just started this unit yesterday, i will make sure to revise!

great, glad you appreciate the help!:smile:
 

FAQ: What Is the Car's Acceleration Given These Forces?

What are Newton's three laws of motion?

Newton's first law states that an object at rest will remain at rest and an object in motion will remain in motion at a constant velocity unless acted upon by an external force. The second law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. The third law states that for every action, there is an equal and opposite reaction.

How do Newton's laws apply to everyday life?

Newton's laws can be observed in many everyday situations. For example, when you push a shopping cart, you are applying a force to move it (Newton's first law). When you step on the gas pedal in a car, the car accelerates (Newton's second law). And when you jump off a diving board, the force of your feet pushing down on the board propels you upwards (Newton's third law).

What is the relationship between force, mass, and acceleration?

Newton's second law, F=ma, describes the relationship between force, mass, and acceleration. This means that the greater the force applied to an object, the greater its acceleration will be. However, if the mass of the object increases, its acceleration will decrease.

How do Newton's laws differ from Galileo's principle of inertia?

Galileo's principle of inertia is similar to Newton's first law, which states that objects at rest will remain at rest unless acted upon by an external force. However, Newton's first law also includes the concept of objects in motion remaining in motion unless acted upon by an external force, which was not included in Galileo's principle.

Can Newton's laws be applied to all types of motion?

Yes, Newton's laws can be applied to all types of motion, including linear, rotational, and orbital motion. They also apply to both macroscopic and microscopic objects, from a simple pendulum to the movement of planets in our solar system.

Similar threads

How Do You Calculate Race Car Acceleration and Power Output?
Replies
20
Views
1K
What Is The Maximum Force The Locust Exerted on The Plate?
Replies
24
Views
2K
Newton's Second Law: Car and Rock Problem
Replies
4
Views
3K
Unbalanced force to find altitude of airplane
Replies
4
Views
1K
Newton's law problem: Helicopter lifting a box with a rope
Replies
5
Views
2K
Rocket acceleration problem: confused about Newton's 2nd Law
2
Replies
42
Views
4K
Two forces acting on an object given in vectors - SOLVED
Replies
1
Views
932
Applying Newton's laws to find forces
Replies
8
Views
14K
Cars rounding a slippery banked corner in the rain
Replies
20
Views
3K
Newton's law to find acceleration
Replies
2
Views
2K

Hot Threads

Recent Insights

Back
Top