Question

A 1200 kg car reaches the top of a 100 m high hill at A with a speed vA. What is the value of vA that will allow the car to coast in neutral so as to just reach the top of the 150 m high hill at B with vB = 0? Neglect friction.

Answer 1

Answer:

the value of vA that will allow the car to coast in neutral so as to just reach the top of the 150 m high hill at B with vB = 0 is 31.3 m/s

Explanation:

given information

car's mass, m = 1200 kg

$h_{A}$ = 100 m

$v_{A}$ = $v_{A}$

$h_{B}$ = 150 m

$v_{B}$ = 0

according to conservative energy

the distance from point A to B, h = 150 m - 100 m = 50 m

the initial speed $v_{A}$

final speed  $v_{B}$ = 0

thus,

$v_{B}$² = $v_{A}$² - 2 g h

0 = $v_{A}$² - 2 g h

$v_{A}$² = 2 g h

$v_{A}$ = √2 g h

    = √2 (9.8) (50)

    = 31.3 m/s