Physics 3

Question 1

What is the order of the planets from the Sun?

Answer 1

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

Question 2

What is the gravitational field strength on Earth?

Answer 2

10 N/kg

Question 3

What are control forces?

Answer 3

Arrows start at the point of contact

Question 4

What are non-control forces?

Answer 4

Arrows start (usually) in the center of mass of the object

Question 5

List of control forces

Answer 5

• Reaction
• Drag or air resistance
• Friction
• Upthrust
• Thrust
• Lift
• Tension

Question 6

List of non-control forces

Answer 6

• Weight
• Magnetic
• Electrostatic
• Nuclear Strong Force

Question 7

What is Weight?

Answer 7

The force due to gravity. An object’s weight will depend on where it is.

e.g. on the Moon an object will have less weight.

Question 8

What is Reaction?

Answer 8

When an object is placed on a surface, the surface will push back on the object (to stop it falling straight through the surface)

Question 9

What is Drag or Air resistance?

Answer 9

When an object moves through a fluid (gas or liquid) it has to push the fluid aside. Therefore, the fluid will push back on the object.

Question 10

What is Friction?

Answer 10

This is the force that tries to stop two surfaces slipping over each other.

Question 11

What is Upthrust?

Answer 11

When an object is placed in a fluid it will experience a force upwards. This force will attempt to keep the object afloat but it will only float if the overall density of the object is less than the surrounding fluid.

Question 12

What is Thrust?

Answer 12

This force can be produced by a jet engine or propellers of an aircraft and it drives an object forward (or backwards).

Question 13

What is Magnetic?

Answer 13

This force attracts a magnetic material to a magnet or can cause two magnets to repel each other (when the same poles are nearest to each other).

Question 14

What is Electrostatic?

Answer 14

This force acts between charged particles or charged objects. Like charges repel while unlike charges will attract each other.

Question 15

What is Nuclear Strong Force?

Answer 15

This force holds together the particles inside a nucleus. This force can’t reach very far so it doesn’t affect particles that aren’t in the nucleus.

Question 16

What is Lift?

Answer 16

This force enables things to fly.

e.g. birds, planes and frisbees.

Question 17

What is Tension?

Answer 17

All materials stretch when subjected to a pulling force. When a material is stretched, the material will pull back on the object, in an attempt to return to its original size.

Question 18

What’s the difference between Scalar and Vectors?

Answer 18

Scalar - have size (magnitude)
Vector - have direction (and magnitude)

Question 19

Examples of scalar quantities

Answer 19

• Mass
• Distance
• Speed
• Energy
• Time

Question 20

Examples of vector quantities

Answer 20

• Weight
• Displacement
• Velocity
• Force
• Acceleration

Question 21

What is acceleration?

Answer 21

The rate of change of velocity.

Question 22

What does gradient equal?

Answer 22

Gradient = velocity

Question 23

Gradients in distance time graphs

Answer 23

1. Constant gradient -> constant velocity (speed is maintained)
2. Gradient = 0 -> velocity 0 (no movement)
3. Gradient increasing -> velocity increasing (acceleration)
4. Decreasing gradient -> decreasing velocity (deceleration)
5. Negative constant gradient -> constant negative velocity (maintain speed)

Question 24

How to find the gradient in distance time graphs?

Answer 24

^ distance / ^ time = gradient = acceleration

Question 25

What units are gradient in?

Answer 25

metres/seconds then / seconds = metres/seconds²

Question 26

How to find the average velocity?

Answer 26

initial velocity + final velocity / 2

Question 27

How to find distance travelled using distance gradient graphs?

Answer 27

By finding the area of said shape.

Question 28

What do magnetic fields look like?

Question 29

List magnetic materials

Answer 29

- Iron - Nickel - Cobalt - Steel ## Footnote These are all hard metals (because once they get magnetized they will remain a permanent magnet).

Question 30

What is the right hand grip rule?

Question 31

What is the right hand grip rule? (2)

Question 32

How to make a relay and bells?

Answer 32

1. Make the electromagnet by winding about 50 turns of thin insulated wire onto the iron U core. 2. Use clamps and stands to arrange the apparatus as outlined in the diagram. 3. You can use the same power supply for the lamp and electromagnet circuits. 4. Take care not to overheat the coils of wire on the electromagnet. You should find that when the electromagnet is switched on, the hacksaw blade touches the 4 mm plug and completes the lamp circuit. ## Footnote This is known as a relay.