Question

A toy car (0.50 kg) runs on a frictionless track and has an initial kinetic energy of 2.2 J, as the drawing shows. The numbers beneath each hill give the heights of the hills. Over which of the hills will the car coast?

KE= 2.2J Hill
A= 0.1M Hill
B= 0.2M Hill
C= 0.3M Hill
D= 0.4M Hill
E= 0.5M
A) A + B
B) A, B, C and D
C) A, B, C, D and E
D) A
E) A, B and C

Answer 1

C) A, B, C, D and E

Step-by-step explanation:

The kinetic energy of the car is converted to potential energy at every point it stop on the hill and converted back to kinetic energy when it costs. So we can say that ;

K.E = 1\2mv^2 = mgh

where;

mgh= P.E is potential energy

K.E is kinetic energy

m = mass of the toy car

v = velocity of the car

h = heights of the hill

g = acceleration due to gravity

From the formula v is the velocity with which the car coast which is calculated for each if the hills thus;

V= √2gh

Hill A, V=√(2*9.81*0.1) = 1.4 m/s

Hill B, V=√(2*9.81*0.2) = 1.98 m/s

Hill C, V=√(2*9.81*0.3) = 2.43 m/s

Hill D, V=√(2*9.81*0.4) = 2.80 m/s

Hill E, V=√(2*9.81*0.5) = 3.13m/s

From the results we can see that the will coast over all the hills but will coast faster from hill E