A porter lifts a luggage of 15 kg from the ground and pats it on his head 1.5 m above the ground. Calculate the work done by him on the luggage.
250 J
235 J
225 J
215 J
A boy of mass 50 kg runs up staircase of 45 steps in 9 s. If the height of each step is 15 cm, find his power. Take g = 10 m s-1
400 W
275 W
375 W
575 W
Unit of workdone is
Newton(N)
Watt(W)
Joule(J)
Pascal
Two bodies of equal weight are kept at heights of h and 1.5 h respectively.The ratio of their P.E. is
1:2
2:3
1:3
2:4
The energy used in households, industries and commercial establishments are usually expressed in
Joule
Watt
Kilowatt - hour
Volt
Which is the correct expression for potential energy of an object?
mgh
1/2 mv2
2mgh
mgh2
1 hp is equal to
0.746 kW
7.46 kW
74.6 kW
746 kW
1 kilo watt =
10 watts
100 watts
500 watts
1000 watts
A person pulls a body on a horizontal surface by applying a force of 5.0 N at an angle of 300 with the horizontal.Find the workdone by this force in displacing the body through 2.0 m?
5√3 J
6√2 J
7√3 J
4√3 J
An object of mass 12 kg is at a certain height above the ground. If the potential energy of the object is 480 J,find the height at which the object is with respect to the ground. Given g = 10 ms-2
4 m
4 mm
40 m
400 m
