Question

When a belt moves horizontally at a constnat speed of 1.5 ms-1, gravel is falling on it at 5 kg s-1. Then the extra power needed to drive

the belt is (a) 11.25 W

(c) 7.5 W

(b) 37.5 W

(d) 0.75 W​

Answer 1

Answer:

Velocity of belt v=1.5 ms−¹

Rate at which the mass of gravel falls

dt/dm =5 kgs −¹

∴ Force acting on the gravel F= dt/dp = dt/dm

v=5×1.5=7.5N

Power needed

P= Fv=7.5×1.5

=11.25 W