Homework Help: Physics

Posted by Haley on Thursday, May 10, 2012 at 8:41pm.

A 4.00 103-kg car has a speed of 9 m/s. The car then hits a tree. The tree doesn't move and the car comes to rest.
(a) Find the change in kinetic energy of the car.
. J
(b) Find the amount of work done in pushing in the front of the car.
J
(c) Find the size of the force that pushed the front of the car in 50 cm.

- i got -2.00e+05 for the first answer and -4.00e+05 for the third, but neither worked?

Physics - Elena, Friday, May 11, 2012 at 1:20am
ΔKE =KE2 – KE1 = 0 - m•v²/2 =
= 4000• 9² /2 = - 162000 J.
a =v² /2•s =9² /2• 0.5= 81 m/s²
F =ma =4000•81 = 324 000 N

Answer this Question

Related Questions

Physics - A car is being driven along a country road on a dark and rainy night ...
physics- pls help me - 1. The driver of a car slams on the brakes when he sees a...
Physics - A mechanic pushes a 3.6 multiplied by 103 kg car from rest to a speed ...
physics - A 2.9 × 103 kg car accelerates from rest at the top of a ...
physics - A car has a mass of 1.56 × 103 kg. If the force acting on the ...
phys - A mechanic pushes a 2.0 103 kg car from rest to a speed of v, doing 5350 ...
physics - A mechanic pushes a 2.60 103-kg car from rest to a speed of v, doing 4...
physics - A 2.1 103-kg car starts from rest at the top of a 5.9-m-long driveway ...
physics - A 2.1 103-kg car starts from rest at the top of a 5.9-m-long driveway ...
physics - A 2.10 103 kg car starts from rest at the top of a 5.8 m long driveway...

For Further Reading

First Name:
School Subject:
Answer: