Calculate the power of an engine required to lift 105kg of coal per hour from a mine 360m deep. (take g= 10ms-2)
1000kW
200kW
100kW
A body falls freely under gravity.If its speed is U when it has cost an amount U of gravitational potential energy,then its mass is
U2/g
U2g/V2
U/V2
2U/V2
When a body moves at an angle θ to the direction of force,work done is given by
F x S
F x s cos θ
F / S
F cos θ / s
A body when acted upon by a force 10 kgf, gets displaced by 0.5 m. Calculate the work done by the force, when the displacement is in the direction of force.
50 J
49 J
5 J
4.9 J
A force of 15 N is required to pull up a body of mass 2 kg through a distance 5 m along an inclined plane making an angle of 30o with the horizontal as in given figure.Then the work done by the force in pulling the body is
15 J
30 J
75 J
1 kilo calorie=
4018 J
4180 J
4280 J
418 J
An ox can apply a maximum force of 1000 N. It is taking part in cart race and is able to pull the cart at constant speed of 30 ms-1 while making its best effort. The power developed by the ox is
300 kW
3000 W
30 kW
If the velocity of a moving body is doubled,the kinetic energy will be
Doubled
Halved
Four times
One-fourth
5 kWh =
1.8 x 107 J
18 x 107 J
0.18 x 107 J
180 x 104 J
The momentum P and kinetic energy K of a moving body are related as
P= 2 m K
P = K / 2 m
K = P2 / 2m
2mP2
