Forces and Motion

Question 1

Describe Weight

Answer 1

➢ The weight of an object is the pull of gravity on it.
➢ It always acts vertically downwards
➢ Contact forces stops you from falling through the floor

Question 2

What is Friction?

Answer 2

➢ It opposes motion, for example when a object is moving in an direction at a speed, friction acts against it.

Question 3

What is Air-resistance?

Answer 3

➢ Air resistance also known as drag is the friction force which acts on an object when It is moving in air or water.

Question 4

What is Upthrust

Answer 4

➢ It is the upward push of liquid or gas on an object.

Question 5

What is Resultant force?

Answer 5

➢ Resultant force is the single force that has the same effect as two or more forces acting together.
➢ If no resultant forces acts on an object, it will not accelerate; it would either be still or in an constant speed.

Question 6

Weight Formula

Answer 6

Weight = Mass x gravitational field strength

Question 7

Difference between Mass and Weight?

Answer 7

➢ The mass of an object, tells you how much matter it is composed of.
➢ The weight of an object, is the gravitational force that acts on it.

Question 8

Terminal Velocity

Answer 8

➢ The constant speed that a freely falling object eventually reaches when the resistance of the medium through which it is falling prevents further acceleration.
➢ For an object following a circular path, the object is acted on by a force at right angles to it’s velocity.

Question 9

Forces in a circle

Answer 9

The force that keeps an object moving in an circle always acts towards the center of the circle. If the force disappears, the object will move off at a tangent to the circle; it will not fly outwards, away from the center.

Question 10

Force

Answer 10

➢ The action of one body on a second body that causes it’s velocity to change.

Question 11

Force Formula

Answer 11

Force = Mass x Acceleration

Question 12

Idea of Momentum

Answer 12

Impulse of force = change of momentum

Impulse = force x time for which it acts = ft momentum = mass x velocity = mv

Total momentum before = Total momentum after

Question 13

Law of conversation of momentum

Answer 13

Law of conservation of momentum states that. For two or more bodies in an isolated system acting upon each other, their total momentum remains constant unless an external force is applied.