P10- Forces and motion 🚙

Question 1

RECAP: What is Newton’s first law [of motion] ? 🍏

Hint: zero resultant force= object

Answer 1

• Newton’s first law is:
• if the resultant force acting on a stationary object is zero, them the object will remain stationary
• ; if the resultant force acting on a moving object is zero, then the object will continue moving in the same direction, at the same speed [with the same velocity]

Question 2

What is Newton’s second law of motion? 🍏

Hint: F= ma

Answer 2

• Newton’s second law of motion states:
• the acceleration of an object is proportional, to the resultant force acting on the object.
• ; the acceleration acting on the object is inversely proportional to the mass of the object.

Question 3

What does it mean that the acceleration of an object, is proportional to the resultant force acting on an object ?

Hint: greater

Answer 3

• the acceleration of an object, being proportional to the resultant force acting on an object means:
• if both objects experience a resultant force, the object with a greater force will have a greater acceleration

Question 4

What does it mean that the acceleration is inversely proportional to the mass of an object ?

Hint: larger

Answer 4

• if the mass is larger, the object with a larger mass will have a smaller acceleration.
• this is because the acceleration, is inversely proportional to the mass of the object

Question 5

• Fill in the gaps: cars travel at __m/s on a main road in the UK
• ; however, cars typically travel at __m/s on a motorway

Answer 5

• cars travel at 13m/s on a main road in the UK
• ; however, cars typically travel at 30m/s on a motorway

Question 6

• Fill in the gaps: to accelerate from a main road to a motorway, it typically involves an acceleration of _m/s.
• but for a typical family car, this would require a force of _____ N

Answer 6

• to accelerate from a main road to a motorway, it typically involves an acceleration of 2m/s
• but for a typical family car, this would require a force of 2000 N

Question 7

What is the definition of ‘inertia’ ?

Hint: uniform

Answer 7

• inertia is the tendency of an object to stay at rest, or to continue in uniform motion.
• this means, objects will stay still or keep the same motion unless, you apply a resultant force

Question 8

What is the definition of the term ‘inertial mass’ ?

Hint: velocity

Answer 8

• inertial mass, is the ratio of the force needed to accelerate an object, over the acceleration produced.
• this simply means, inertial mass is a measure of how difficult it is to change the velocity of an object

Question 9

What does inertial mass mean ?

Hint: measure

Answer 9

• inertial mass, is a measure of how difficult it is to change the velocity of an object

Question 10

• Fill in the gaps: inertial mass, simply means a ______ of how difficult it is to change the velocity of an object
• an object with a _____ inertial mass, will require a larger force to produce a given ____________ than an object with a smaller inertial mass.

Answer 10

• inertial mass, simply means a measure of how difficult it is to change the velocity of an object
• an object with a large inertial mass, will require a larger force to produce a given acceleration, than an object with a smaller inertial mass.

Question 11

RECAP: What is Newton’s third law of motion ? 🍏

Hint: exert

Answer 11

• newton’s third law of motion is:
• whenever two objects interact, the forces they exert on each other are equal and opposite.

Question 12

What’s an example, of Newton’s third law of motion ?

Hint: reverse

Answer 12

• when a car is driving, the wheel exerts a force in the reverse direction on the road.
• ; at the same time, the road exerts a force in the forward direction on the wheel.
• these two forces are equal in magnitude, but opposite in direction.

Question 13

What is terminal velocity ?

Hint: steady

Answer 13

• terminal velocity, is when an object moves at a steady speed, in a constant direction.
• this is because, the resultant force acting on it is zero.

Question 14

What does terminal velocity apply to ?

Answer 14

• terminal velocity, also applies to any object falling through a fluid [e.g- water or air]

Question 15

What happens when a skydiver falls 🪂 ?

Hint: upwards force, balance- why?, terminal velocity

Answer 15

• as a skydiver falls, they experience air resistance with the air particles
• and after some time, the force of air resistance will balance the force, due to gravity.
• the object will then stop accelerating at this point, and it will move at a terminal velocity

Question 16

• Fill in the gaps: the ________ velocity an object reaches, will depend on the object.
• For example, some objects may experience a _______ force of friction because of their shape.
• This means they’ll have a lower _________ velocity.

Answer 16

• the terminal velocity an object reaches, will depend on the object.
• For example, some objects may experience a greater force of friction because of their shape.
• This means they’ll have a lower terminal velocity.

Question 17

What is mass ?

Answer 17

• mass, is the quantity of matter in an object
• ; it can also be known as, a measure of the difficulty of changing the motion of an object

Question 18

What is the unit of mass ?

Answer 18

• the unit of mass is the kilogram [kg]- this is the standard unit for mass, and therefore it is never converted

Question 19

• Fill in the gaps: the mass of an object, doesn’t ______ on where the object is unlike weight.

Answer 19

• the mass of an object, doesn’t depend on where the object is unlike weight.

Question 20

RECAP: What is weight ?

Hint: due to

Answer 20

• weight, is the force acting on an object due to gravity.
• and the unit of weight, is the newton (N)

Question 21

• Fill in the gap: unlike mass, ______ does depend on where it is.
• and the ______ of an object, is directly proportional to the mass of an object.
• this means if the weight is doubled, so is the mass

Answer 21

• unlike mass, weight does depend on where it is.
• and the weight of an object, is directly proportional to the mass of an object.
• this means if the weight is doubled, so is the mass

Question 22

RECAP: What is gravational field strength ?

Hint: in a particular

Answer 22

• gravitational field strength, is a measure of the force of gravity, in a particular location.
• ; the gravitational field strength, depends on where you are.