(1) a car travelling at a constant speed of 20ms-1 overcomes a constant frictional resistance of 300N. What is the horse power of the engine? ( take 1h.p = 3/4 kw)

Answer 1

6000 Nm/s = 6 kw

Answer 2

M=f×s/t

Answer 3

Recall;

Power = force x distance/time

also recall distance/time = velocity

also recall; Nm/s = Watts

Hence;

Power = 300N x 20m/s

Power = 6000Nm/s

Power = 6000watts or 6kw

Recall;

750watts = 1hp

but 1hp = 3/4kw

therefore;

750watts = 3/4kw

0.75kw 3/4kw

0.75kw = 3/4kw

6kw = xhp

Therefore;

xhp = 3/4 x 6/0.75

xhp = 4.5/0.75

xhp = 6hp

Answer 4

Recall;

Power = force x distance/time

also recall distance/time = velocity

also recall; Nm/s = Watts

Hence;

Power = 300N x 20m/s

Power = 6000Nm/s

Power = 6000watts or 6kw

Recall;

750watts = 1hp

but 1hp = 3/4kw

therefore;

1hp = 0.75kw

xhp = 6kw

Therefore;

0.75 * xhp = 6* 1

xhp = 6/0.75

xhp = 8hp

Corrected

Answer 5

It is correct