Plz solve the physics question ?

Question

An electric motor outputs 1500 W of power in pulling a 70 kg crate of fish up a very slippery

loading ramp at a constant speed. The ramp is inclined 31∞ to the horizontal. Determine the

speed of the crate. (Ignore friction.)

Answer 1

Mass m = 70 kg

Component of weight along the ramp = mg sin 31 deg

This component is down the ramp.

Since the speed is constant, therefore force applied by motor is up the ramp and has magnitude

F = mg sin 31 deg = 70*9.8*sin 31 deg

Force * speed = power

speed = power/force = 1500/(70*9.8*sin 31 deg)

= 4.2 m/s

Ans: 4.2 m/s

Answer 2

Power  P is force F times speed v. We have

P=F v

Apposing the motion is the force is due to gravity and along the plane. We have

F= mg sin(31)

v = P/F= P/(mg sin(31))

v= 1500 / (70 x 9.81 x sin(31))=

v=4.2 m/s

Answer 3

Watt = J / s = N * m/s = kg * m/s/s * m/s

= mass * acceleration * velocity

= m * a * v

a = g * sin Ó¨;  for inclined plane

So,

1500 W = 70kg * 9.8 sin 31 * v

1500 = 70 * 9.8 * 0.515 * v

v = 1500 / 353.29 = 4.2 m/s