1.2 Dynamics

Question 0

Give a few examples of forces…

Answer 0

Weight, friction, thrust, lift, magnetic

Question 1

What does force change?

Answer 1

Speed, direction and shape of an object.

Question 2

What is used to measure force?

Answer 2

A newton balance. 1N = 1cm extension

Question 3

What is weight?

Answer 3

The Earth’s pull on an object.

Question 4

Is weight a scalar or vector quantity?

Answer 4

vector

Question 5

What are the symbol and unit for weight?

Answer 5

W and newtons (N)

Question 6

What is the equation for weight?

Answer 6

W=mg

weight equal mass times gravitational field strength

Question 7

What is mass?

Answer 7

The measure of matter within an object.

Question 8

Is mass a scalar or vector quantity?

Answer 8

scalar

Question 9

What are the unit and symbol for mass?

Answer 9

m and kilograms (kg)

Question 10

What is gravitational field strength?

Answer 10

The weight per unit mass.

Question 11

What are the symbol and unit of gravitational field strength?

Answer 11

g and newtons per kilogram (N/kg)

Question 12

What is the value of gravitational field strength on Earth?

Answer 12

10N/kg

Question 13

What is the force of friction?

Answer 13

Opposes the motion of the object.

Question 14

In what situations is friction wanted?

Answer 14

sitting, driving, writing, bikes, walking

Question 15

In what situations is friction unwanted?

Answer 15

racing cars, fast cars

Question 16

What can be done to reduce friction?

Answer 16

lubrication, streamlining, ball bearings

Question 17

What is Newton’s 1st Law of Motion?

Answer 17

An object will continue to travel at a constant velocity unless acted on by an unbalanced force.

Question 18

What are balanced forces?

Answer 18

Forces that are opposite in direction but equal in magnitude.

Question 19

Is force a vector or scalar quantity?

Answer 19

vector

Question 20

What is Newton’s 2nd Law of Motion?

Answer 20

Acceleration of an object is directly proportional to the magnitude of unbalanced force acting and inversely proportional to the mass.

Question 21

What is the equation linking force, mass and acceleration?

Answer 21

F=ma

force (F) equals mass (m) times acceleration (a)

Question 22

What is the newton and it’s symbol?

Answer 22

The force needed to accelerate 1kg at 1m/s. (N)

Question 23

What is the resultant force?

Answer 23

The resulting force acting on an object when balanced forces have been subtracted.

Question 24

What is the method of calculating resultant force? (3 steps)

Answer 24

1) free body diagram 2) tip to tail 3) calculate resultant

Question 25

Explain the equivalence of acceleration due to gravity and gravitational field strength…

Answer 25

F=W F=ma W=mg
ma=mg
a=g

Question 26

Which objects does acceleration due to gravity affect and what is its symbol?

Answer 26

objects in freefall accelerate at a rate equal to the acceleration due to gravity. (a)

Question 27

What is a projectile?

Answer 27

An object traveling horizontally and vertically at the same time.

Question 28

Explain the curved path of projectiles in terms of the force of gravity…

Answer 28

Vertically the object accelerates due to gravity and the combined result of horizontal and vertical motion is a curved path.