Answer:
Explanation:
Momentum conservation

Kinetic energy conservation

Solve the system
The strict scientific definition of work is
Work = (force) x (distance) .
If you exert a force but not through any distance, then technically,
no work has been done. You may break out in sweat, and your arm
may start to tremble and ache. But according to Physics, no work
has been done until you lift that bale a little higher.
Answer:
304.89m
Explanation:
Given
acceleration a = 2.52m/s²
final speed v = 39.2m/s
initial speed = 0m/s (car accelerates from rest)
Using the equation of motion below to get the distance of Doc brown from Marty;
v² = u²+2as
substitute the given parameters
39.2² = 0²+2(2.52)s
1536.64 = 0+5.04s
divide both sides by 5.04
1536.64/5.04 = 5.04s/5.04
rearrange the equation
5.04s/5.04 = 1536.64/5.04
s = 304.89m
Hence He and Marty must stand at 304.89m to allow the car to accelerate from rest to a speed of 39.2 m/s?