how much work is required to make a 1400 kg car increase its speed from 10 m/s to 20 m/s?
what average force is required if the car travels 15 m during this speed change?
So I got 70000 J for the first part
The second part is W=fd
W= (1400)(15)
W= 21000 N
F = m a
a = (20-10)/T =10/T
15 meters = 10 T + (1/2) a T^2
but it is easy to get T without doing that because a is constant so average speed * T = 15
15 T = 15
T = 1 second
a = 10 m/s^2 (about 1 g)
F = m a = 1400*10 = 14,000 Newtons
work = constant F * 15 meters = 210,000 Joules