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| Question | Answer | ||||||||||||||||
| Calculate the work done when a force of 20N makes an object move 4.8m in the direction of the force. | 96J | ||||||||||||||||
| Calculate the work done when an object of weight 80N is raised through a height of 1.2m. | 96J | A student of weight 450N steps on a box of height 0.2m, Calculate the gain in gravitational potential energy. | 90J | Calculate the work done by a student of weight 450N if she steps on and off a box of 0.2m high 50 times. | 4500J | State the energy transfers for a student jumping on a trampoline. | Chemical energy --> KE -->GPE --> KE --> EPE | Calculate the Kinetic energy of a cannon ball with mass 50Kg travelling at a speed of 20m/s. | 10,000J | Calculate the momentum of an object with mass 90Kg travelling at a velocity of 5m/s. | 450Kgm/s | What is the momentum of a rocket of mass 50,000Kg just before launch? | OKgm/s | An 800Kg car travelling at 30m/s is stopped safely when the brakes are applied. What deceleration and braking force are required to stop it in 6s? | 5m/s2. 4000N | Explain why an inflated air bag in front of a car user reduces the force on a user in a head-on crash. | It increases the time taken to stop the person. (It also spreads out the force so the effect is lessened) |
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Brainly User Brainly User
Given that:
- What will be the work done when a force of 20 newton displaces an object 4 metres in the same direction.
According to the statement:
- Force = 20 Newton
- Displacement = 4 metres
To calculate:
Solution:
Knowledge required:
• When the force and displacement are in same direction then the work done is positive.
• When the force and displacement are in different direction then the work done is negative.
• SI unit of work done is N/m because the SI unit of force is Newton that is N and SI unit of displacement is metre that is m, when be combined then it be N/m
- But to the honour of scientist that do maximum work on it, the SI unit of work done be Joule
Using concept:
Using formula:
Where, W denotes work done, F denotes force, S denotes displacement.
Full solution:
→ W = F × S
→ W = 20 × 4
→ W = 80 J
→ Work done = +80 Joule
NewGeneEinstein NewGeneEinstein
Explanation:
Given:-
Force=20N
Displacement=4m
To find:-
Work done
Solution:-
We know that