Advertisements
Advertisements
प्रश्न
A man squatting on the ground gets straight up and stand. The force of reaction of ground on the man during the process is ______.
पर्याय
constant and equal to mg in magnitude.
constant and greater than mg in magnitude.
variable but always greater than mg.
at first greater than mg, and later becomes equal to mg.
Advertisements
उत्तर
A man squatting on the ground gets straight up and stand. The force of reaction of ground on the man during the process is at first greater than mg, and later becomes equal to mg.
Explanation:
When the man is squatting on the ground he is tilted somewhat, hence he also has to balance frictional force besides his weight in this case.
R = reactional force = friction + mg
⇒ R > mg
When the man gets straight up in that case friction ≈ 0
⇒ Reactional force ≈ mg
APPEARS IN
संबंधित प्रश्न
Work done = Force × ........................................
Define work.
In which of the following cases is work being done:
- A boy pushing a heavy rock
- A boy climbing up the stairs
- A coolie standing with a box on his head
- A girl moving on the road.
How is work related to energy?
State two advantage of producing hydroelectricity.
State the law of conservation of energy.
Explain by an example that a body may possess energy even when it is not in motion.
A car is being driven by a force of 2.5 ✕ 1010 N. Travelling at a constant speed of 5 m/s, it takes 2 minutes to reach a certain place. Calculate the work done.
Determine the amount of work done when an object is displaced at an angle of 30° with respect to the direction of the applied force.
What is the relationship between Nm and dyne cm?
State the conditions of equilibrium for a rigid body.
What is the work done against gravity when a body is moved horizontally along a frictionless surface?
A weight lifted a load of 200 kgf to a height of 2.5 m in 5 s. calculate: (i) the work done, and (ii) the power developed by him. Take g= 10 N kg-1.
Fill in the boxe to show the corresponding energy transformation.
A canon ball of mass 500g is fired with a speed of 15m/s-1. Find: its momentum.
Name the material commonly used for the manufacturing of solar cells.
A force can cause an object to change its ______.
Work done by this force at any instant is ______.
