Force And The Resultant (T1)

Question 1

What is force measured in?

Answer 1

Newtons - N

Question 2

Is force a vector or scalar?

Answer 2

vector

Question 3

List 6 types of force…

Answer 3

• weight (gravity)
• friction
• air resistance / drag
• normal reaction force
• upthrust
• magnetic

Question 4

When would we say the unbalanced force is zero?

Answer 4

If the force acting on an object is the same value as the force acting in the opposite direction

Question 5

If two teams are playing tug of war and one team is pulling with a greater force than the other, what is happening with regards to force?

Answer 5

There will be an unbalanced force in the direction of the team pulling and the rope will move

Question 6

Define and give an example of ‘balanced force’

Answer 6

When forces acting on something are balanced and the object does not change the way it is moving.

Eg: if two teams are playing tug of war and both teams are pulling with equal force, the rope does not move because the two forces are balanced.

Question 7

Describe the resultant or resultant force..

Answer 7

When two or more forces are acting together we can imagine them being replaced by a single force that has the same effect on its own as the original forces acting together.

The single force is known as the resultant force or resultant.

Question 8

How do you calculate the resultant force?

Answer 8

Simply add the forces acting on an object together and the result is the resultant force.

Eg: two forces, one 25N and one of 30N act on an object with a resultant force of 55N (25 + 30)

Question 9

Describe vector addition and give an example of how it can be used to calculate the resultant..

Answer 9

The resultant can be calculated by adding together other vectors acting on an object. This process is known as vector addition.

Eg: if a javelin thrower is running 3 m/s and throws the javelin at 20 m/s, the resultant = 3 m/s + 20 m/s = 23 m/s.

Question 10

How do you calculate the resultant force if the forces acting on an object are in opposing directions?

Answer 10

When forces are in opposing directions just subtract the smaller one from the bigger one and the resultant is in the direction of the bigger one.

Question 11

If the same force is applied to two objects with different mass, which object will experience the greater acceleration?

Answer 11

The object with smaller mass

Question 12

Explain a typical lab experiment to investigate the relationship between force, mass and acceleration..

Answer 12

• a nylon line with a mass hanger on one side is attached to a trolley with mass weights on it
• the trolley is positioned on a slope and the nylon line runs over a pulley
• a digital camera taking pictures at equal intervals, or a set of light gates or data logger can be used to find the speed at the top and near the end

Question 13

Force is ……. to acceleration

Answer 13

Force is proportional to acceleration.

Doubling the force on an object doubles the acceleration.

Question 14

How do you calculate force?

Answer 14

Force = mass x acceleration

F = ma

Question 15

…. is the force needed to make a mass of …… accelerate at …… per second

Answer 15

1 N is the force needed to make a mass of 1 Kg accelerate at 1 m per second

Question 16

What is meant by the reaction force, or normal reaction force?

Answer 16

The support force exerted on an object that is in contact with another stable object.

Eg: if a book is resting on a surface, that surface is exerting an upward force on the book in order to support the weight of the book.

If greater and greater weights are put on the table, at microscopic level the table’s surface will deform just enough to give a reaction force that perfectly balances the weight.

The resultant force is zero.