Forces questions

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Forces question collection

Review Forces questions for Physics, with correct answers shown and coverage across resultant forces; weight and mass; work done and springs.

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Question 1

A \(5\,\mathrm{kg}\) mass is in a \(10\,\mathrm{N/kg}\) field. What is its weight?
  1. \(50\,\mathrm{N}\)
  2. \(0.5\,\mathrm{N}\)
  3. \(15\,\mathrm{N}\)
  4. \(500\,\mathrm{N}\)

Question 2

A \(10\,\mathrm{kg}\) object experiences a \(20\,\mathrm{N}\) resultant force. What is its acceleration?
  1. \(2\,\mathrm{m/s^2}\)
  2. \(0.5\,\mathrm{m/s^2}\)
  3. \(200\,\mathrm{m/s^2}\)
  4. \(10\,\mathrm{m/s^2}\)

Question 3

Which law links resultant force, mass and acceleration?
  1. Newton's second law
  2. Newton's first law
  3. Newton's third law
  4. Hooke's law

Question 4

Momentum is calculated with which equation?
  1. \(p = mv\)
  2. \(p = m / v\)
  3. \(p = mv^2\)
  4. \(p = m + v\)

Question 5

Which force opposes motion between surfaces?
  1. Friction
  2. Drag
  3. Upthrust
  4. Tension

Question 6

Area doubles while force stays constant. What happens to pressure?
  1. It halves
  2. It doubles
  3. It stays unchanged
  4. It quadruples

Question 7

What is true when forces are balanced?
  1. The resultant is zero
  2. The velocity is zero
  3. The acceleration is non-zero
  4. The momentum is zero

Question 8

A \(50\,\mathrm{N}\) force acts for \(0.2\,\mathrm{s}\). What impulse is delivered?
  1. \(10\,\mathrm{N\,s}\)
  2. \(250\,\mathrm{N\,s}\)
  3. \(50.2\,\mathrm{N\,s}\)
  4. \(0.004\,\mathrm{N\,s}\)

Question 9

At terminal velocity, how do weight and air resistance compare?
  1. They are equal
  2. Weight is greater
  3. Resistance is greater
  4. Both are zero

Question 10

Forces of \(50\,\mathrm{N}\) right and \(10\,\mathrm{N}\) left act on an object. What is the resultant?
  1. \(40\,\mathrm{N}\) right
  2. \(60\,\mathrm{N}\) right
  3. \(40\,\mathrm{N}\) left
  4. \(5\,\mathrm{N}\) right

Question 11

Which equation links work done, force and distance for a constant force?
  1. \(W = Fd\)
  2. \(W = F / d\)
  3. \(W = F + d\)
  4. \(W = Fd^2\)

Question 12

A force speeds an object up. What is the force doing?
  1. Doing positive work
  2. Doing negative work
  3. Not doing work
  4. Acting perpendicular

Question 13

Which quantity is scalar rather than vector?
  1. Speed
  2. Force
  3. Velocity
  4. Acceleration

Question 14

Which quantity is conserved in collisions if no external force acts?
  1. Momentum
  2. Speed
  3. Displacement
  4. Kinetic energy

Question 15

Which equation links pressure P, force F and area A?
  1. \(P = F / A\)
  2. \(P = FA\)
  3. \(P = A / F\)
  4. \(P = F + A\)

Question 16

Why does opening a parachute reduce downward acceleration?
  1. Air resistance increases
  2. Upthrust increases
  3. Weight decreases
  4. Momentum becomes zero

Question 17

Which is a Newton's third-law pair?
  1. Swimmer pushes water; water pushes swimmer
  2. Earth pulls ball; ball accelerates
  3. Table pushes book; Earth pulls book
  4. Magnet pulls iron; friction opposes motion

Question 18

What does the area under a force-extension graph give?
  1. Work done
  2. Spring constant
  3. Extension
  4. Limit of proportionality

Question 19

Which equation defines weight?
  1. \(W = mg\)
  2. \(W = m / g\)
  3. \(W = m + g\)
  4. \(W = m g^2\)

Question 20

What is the approximate value of gravitational field strength \(g\) near Earth?
  1. \(10\,\mathrm{N/kg}\)
  2. \(5\,\mathrm{N/kg}\)
  3. \(100\,\mathrm{N/kg}\)
  4. \(0.1\,\mathrm{N/kg}\)

Question 21

Light travels at \(3.0 \times 10^8\,\mathrm{m/s}\). How far does it travel in \(500\,\mathrm{s}\)?
  1. \(1.5 \times 10^{11}\,\mathrm{m}\)
  2. \(6.0 \times 10^5\,\mathrm{m}\)
  3. \(1.5 \times 10^8\,\mathrm{m}\)
  4. \(1.5 \times 10^{14}\,\mathrm{m}\)

Question 22

Acceleration is the rate of change of what?
  1. Velocity
  2. Distance
  3. Displacement
  4. Momentum

Question 23

Which Newton law says every action has an equal and opposite reaction?
  1. Third law
  2. First law
  3. Second law
  4. Power law

Question 24

Which unit gives pressure?
  1. Newton per square metre
  2. Newton per metre
  3. Newton metre
  4. Joule per second

Question 25

Which change increases a driver's thinking distance?
  1. Higher speed
  2. Worn tyres
  3. Weaker brakes
  4. A wet road

Question 26

A \(20\,\mathrm{N}\) force acts \(0.5\,\mathrm{m}\) from a pivot. What moment does it produce?
  1. \(10\,\mathrm{N\,m}\)
  2. \(40\,\mathrm{N\,m}\)
  3. \(20.5\,\mathrm{N\,m}\)
  4. \(0.025\,\mathrm{N\,m}\)

Question 27

What is the unit of momentum?
  1. \(\mathrm{kg\,m\,s^{-1}}\)
  2. \(\mathrm{N\,kg^{-1}}\)
  3. \(\mathrm{J\,s^{-1}}\)
  4. \(\mathrm{kg\,m^{-3}}\)

Question 28

Braking distance doubles for the same energy. What happens to the force?
  1. It halves
  2. It doubles
  3. It stays unchanged
  4. It quadruples

Question 29

Which equation gives elastic potential energy in a spring?
  1. \(E_e=\frac{1}{2}ke^2\)
  2. \(E_e=ke\)
  3. \(E_e=mgh\)
  4. \(E_e=\frac{1}{2}mv^2\)

Question 30

The upthrust on a submerged object equals the weight of what?
  1. The fluid it displaces
  2. The object itself
  3. The container holding the fluid
  4. The air above the fluid

Question 31

Which property decides whether a solid object floats in water?
  1. Its density
  2. Its mass
  3. Its volume
  4. Its surface area

Question 32

Atmospheric pressure at a surface is caused by the weight of what?
  1. The air above it
  2. The Earth’s crust
  3. Water vapour only
  4. The surface itself

Question 33

Roughly what is atmospheric pressure at sea level?
  1. 100 kPa
  2. 1 kPa
  3. 10 kPa
  4. 1000 kPa

Question 34

What does the gradient of a distance-time graph give?
  1. Speed
  2. Acceleration
  3. Distance
  4. Momentum

Question 35

A distance-time graph is a straight line reaching 60 m at 12 s. What is the speed?
  1. 5 m/s
  2. 0.2 m/s
  3. 48 m/s
  4. 720 m/s

Question 36

What does the area under a velocity-time graph give?
  1. Distance travelled
  2. Acceleration
  3. Average speed
  4. Resultant force

Question 37

A velocity-time graph rises from 0 to 24 m/s in 6 s. What is the acceleration?
  1. 4 m/s²
  2. 0.25 m/s²
  3. 18 m/s²
  4. 144 m/s²

Question 38

Inertial mass measures resistance to a change in what?
  1. Velocity
  2. Position
  3. Temperature
  4. Shape

Question 39

Two objects feel the same resultant force. Which one accelerates less?
  1. The heavier object
  2. The lighter object
  3. The faster object
  4. The larger object

Question 40

What is a typical human reaction time?
  1. 0.2 to 0.9 s
  2. 0.01 to 0.05 s
  3. 2 to 5 s
  4. 10 to 20 s

Question 41

Which of these increases a driver’s reaction time?
  1. Tiredness
  2. An icy road
  3. Worn brake pads
  4. Under-inflated tyres

Question 42

Which condition increases the braking distance of a car?
  1. An icy road
  2. A dry road
  3. New brake pads
  4. A slower speed

Question 43

Which of these affects how far a car travels once it starts to slow, rather than the driver’s reaction time?
  1. Worn brake pads
  2. Tiredness
  3. Drinking alcohol
  4. Using a mobile phone

Question 44

An object moves in a circle at constant speed. What is changing?
  1. Its velocity
  2. Its speed
  3. Its mass
  4. Its kinetic energy

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Review Forces questions for Physics, with correct answers shown and coverage across resultant forces; weight and mass; work done and springs.

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