A motorcycle moving at a constant velocity suddenly accelerates at a rate of 4.0 m/s^2 to a speed of 35 m/s in 5.0 s. What was the initial speed of the motorcycle?

Explanation:

Step one:

given data

acceleration a=4m/s^2

final velocity v=35m/s

time t=5 seconds

Step two:

Required

initial velocity u=?

Applying the first equation of motion

v=u+at

substituting we have

35=u+4*5

35=u+20

u=35-20

u=15 m/s

The initial velocity is 15m/s

b.a device that inputs heat into a cool object