Physics
posted by Lindsay .
A 850.0kg car travelling on a level road at 27.0 m/s (60.5 mi/hr) can stop, locking its wheels, in a distance of 61.0 m (200.1 ft).
(a) Find the size of the horizontal force which the car applies on the road while stopping.
(b) Find the stopping distance of that same car when it is traveling up a 18.1 deg slope, and it locks its wheels while traveling at 34.7 m/s (77.7 mi/hr). Assume that muk does not depend on the speed.
This is making no sense to me. Can I please have some help?

(a) (Force) x (stopping distance) = kinetic energy converted to heat
= (1/2) M V^2
Solve for F
(b) In this case, the initial kinetic energy is converted to both gravitational potential energy and heat.
The horizontal force will be whatever you get in Part (a), multiplied by cos 18.1 (0.9505). That is becasue the kinetic friction force is proportion to the normal component of the weight. Call this force F'
(Frictional work done) + (Potential energy increase) = (Initial kinetic energy)
F'*X + M g (X sin 18.1) = (1/2) M V^2
Solve for the new value of X.
The second term on the left is the increase in gravitational potential energy as the car sises up the slop. 
I came up with 5079 N as my answer to a. Is that correct?

Yeppp n/m it is correct. Thanks a lot. :)
Respond to this Question
Similar Questions

Physics
A 1100 kg car is moving toward the north along a straight road at a speed of 20.0 m/s. The driver applies the brakes and the car comes to rest in a distance of 140 m. (a) If the road is completely level, what is the constant force … 
Physics
A 1100 kg car is moving toward the north along a straight road at a speed of 20.0 m/s. The driver applies the brakes and the car comes to rest in a distance of 140 m. (a) If the road is completely level, what is the constant force … 
physics
the driver of a 1200kg car travelling 45km/h west on a slippery road applies the brakes, skidding to a stop in 35m. Determine the coefficient of friction between the road and the car tires 
Physics
A car of mass 1550 kg is travelling at 75.0 km/h on a dry horizontal concrete surface when the driver applies the brakes licking the wheels. (a) How far does the car travel before coming to rest? 
physics
A car, mass  1950 kg, accelerates at +2.33 m/s (squared). Find the magnitude of the normal force acting on the car. If later, when the car is cruising at 26.5 m/s, the driver applies a force of magnitude 10,000 N to stop the car. … 
Physics
a train is moving at 45km/h when a coupling breaks and the last car separates from the train. as soon as the car separates, the brakes are automatically applied, locking all wheels of the runaway car and causing a uniform decelaration … 
Physics
A car travels at 64 mi/h when the brakes are suddenly applied. Consider how the tires of a moving car come in contact with the road. When the car goes into a skid (with wheels locked up), the rubber of the tire is moving with respect … 
Physics
The driver of a car on a horizontal road makes an emergency stop by applying the brakes so that all four wheels lock and skid along the road. The coefficient of kinetic friction between tires and road is 0.39. The separation between … 
Physics
1) A car moving along a straight stretch of road at 60 mph [26.7 meters/sec]. The driver makes slams on his breaks locking them so that the car skids to a stop. Assume a constant braking force due to friction, and a kinetic friction … 
physics
A car has a mass of 1500 kg. If the driver applies the brakes while on a gravel road, the maximum friction force that the tires can provide without skidding is about 7000 N. If the car is moving at 18 m/s, what is the shortest distance …