Advertisements
Advertisements
प्रश्न
The work done by a fielder when he takes a catch in a cricket match, is negative. Explain.
Advertisements
उत्तर
When a cricket player catches a ball, he exerts force against the direction of the ball, which results in negative work.
APPEARS IN
संबंधित प्रश्न
Give an example when work done by the force of gravity acting on a body is zero even though the body gets displaced from its initial position.
What physical quantity does the electron volt (eV) measure? How is it related to the S.I. unit of that quality?
A body, when acted upon by a force of 10 kgf, gets displaced by 0.5 m. Calculate the work done by the force, when the displacement is (i) in the direction of force, (ii) at an angle of 60° with the force, and (iii) normal to the force. (g = 10 N kg-1)
An ox can apply a maximum force of 1000 N. It is taking part in a cart race and is able to pull the cart at a constant speed of 30 ms-1 while making its best effort. Calculate the power developed by the ox.
Name two places in india where electricity is generated from nuclear power plants.
The moment of a force 10 N about a point 0 is 4 Nm. Calculate the distance of point of application of force from the point 0.
A pump is used to lift 600 kg of water from a depth of 75 m in 10s. Calculate:
- The work done by the pump,
- the power at which the pump works, and
- The power rating of the pump if its efficiency is 40%. (Take g = 10m s-2).
`["Hint" : "Efficiency" = "useful power"/"power input"]`
A man raises a box of mass 50 kg to a height of 2 m in 20s, while another man raises the same box to the same height in 50s. Calculated:
- the work done, and
- the power developed by each man. Take g = 10 N kg-1.
How is 1 kgf related to the SI unit of force?
For the following scenario, state whether the work done by gravity is positive, negative, or zero.
A person walks on a levelled road.
