حرکیات اور قوت

Written by Dr. Hamza Farooq (Physics)

نویں جماعت · طبیعیات · 10 سوالات

نام: ____________________ تاریخ: ____________

Newton's first law of motion is also called the law of:
- A Gravitation
- B Acceleration
- C Momentum transfer
- D Inertia
What force is needed to give a mass of 5 kg an acceleration of 3 m/s²?
- A 8 N
- B 1.7 N
- C 15 N
- D 2 N
What is the SI unit of momentum?
- A kg m/s²
- B N
- C J
- D kg m/s
When a gun fires a bullet, the gun recoils. This is explained by:
- A Newton's second law
- B Newton's first law
- C Newton's third law
- D Law of gravitation
What is the weight of a 10 kg mass on Earth? (g = 10 m/s²)
- A 10 N
- B 1 N
- C 100 N
- D 0.1 N
The force that opposes the motion of one surface over another is called:
- A Thrust
- B Friction
- C Tension
- D Gravity
Inertia of a body depends on its:
- A Colour
- B Mass
- C Shape only
- D Temperature
Newton's second law is written as:
- A F = m / a
- B F = m + a
- C F = m a
- D F = a / m
What is the momentum of a 0.5 kg ball moving at 4 m/s?
- A 2 kg m/s
- B 0.125 kg m/s
- C 4.5 kg m/s
- D 8 kg m/s
Rolling friction is generally ___ sliding friction.
- A More than
- B Double
- C Less than
- D Equal to

جوابی کلید

1. D, 2. C, 3. D, 4. C, 5. C, 6. B, 7. B, 8. C, 9. A, 10. C

A body stays at rest or in uniform motion unless a net force acts on it. This property is inertia.
F = m a = 5 x 3 = 15 N.
Momentum = mass x velocity, so its unit is kg m/s.
The force on the bullet has an equal and opposite reaction force on the gun.
W = m g = 10 x 10 = 100 N.
Friction acts between surfaces in contact and opposes relative motion.
A larger mass has a larger inertia.
Force equals mass times acceleration.
p = m v = 0.5 x 4 = 2 kg m/s.
Rolling friction is smaller, which is why wheels are useful.