Four persons jointly lift a 250 kg box to a height of 1 m and hold it.
a) Calculate the work done by the persons in lifting the box.
b) How much work is done for just holding the box
c) Why do they get tired while holding it ? (g= 10 m/s2)
Answers
Answer:
a.)
✭ F = ma ✭
Where,
- F is the force applied by the man in lifting the box.
- m is the mass of the box.
- a is the acceleration due to gravity.
Putting the values in the formula, we have:
➥ F = 250 × 10
➥ F = 2500 N
Given:
Displacement in the direction of force of lifting the box ( s ) = 1 m
✭ W = F × s
Where,
- W is the work done by the persons in lifting the box.
- F is the force applied by the man in lifting the box.
- s is the displacement in the direction of force of lifting the box.
Putting the values in the formula, we have:
➥ W = 2500 × 1
➥ W = 2500 J
∴ The work done by the persons in lifting the box = 2500 J
b.)
➥ Zero work is done for just holding the box. As there is no displacement while just holding the box, that is there is no distance covered between the initial and the final position, therefore there is no work done or in other words you can say that work done is zero.
c.)
➥ In order to hold the box men is applying a force against the gravity. The men are applying equal and opposite force to the gravitational force, which is acting on the box. So while applying the force, their muscles are are involved or you can say muscular effort is involved, so they feel tired while holding the box.
_______________________________
Answer:
Answer:
a.)
✭ F = ma ✭
Where,
F is the force applied by the man in lifting the box.
m is the mass of the box.
a is the acceleration due to gravity.
Putting the values in the formula, we have:
➥ F = 250 × 10
➥ F = 2500 N
Given:
Displacement in the direction of force of lifting the box ( s ) = 1 m
✭ W = F × s
Where,
W is the work done by the persons in lifting the box.
F is the force applied by the man in lifting the box.
s is the displacement in the direction of force of lifting the box.
Putting the values in the formula, we have:
➥ W = 2500 × 1
➥ W = 2500 J
∴ The work done by the persons in lifting the box = 2500 J
b.)
➥ Zero work is done for just holding the box. As there is no displacement while just holding the box, that is there is no distance covered between the initial and the final position, therefore there is no work done or in other words you can say that work done is zero.
c.)
➥ In order to hold the box men is applying a force against the gravity. The men are applying equal and opposite force to the gravitational force, which is acting on the box. So while applying the force, their muscles are are involved or you can say muscular effort is involved, so they feel tired while holding the box.
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Explanation:
Hope this answer will help you.✌️