Seesaw Balance Forces

A nut can be loosened more easily with

• a short spanner because a larger turning effect can be produced.

• a long spanner because a larger turning effect can be produced.

• a long spanner because a larger force can be produced.

• a short spanner because a larger force can be produced.

A see-saw is made by resting a long plank of wood with its centre of gravity on the barrel.

A boy sits on one side of the barrel and a girl sits on the other side so that the see-saw is balanced.

Which of the following statements must be true?

• boy’s weight = girl’s weight

• distance x = distance y

• moments of the girl = moments of the boy

• moment of the girl > moment of the boy

Tags

NGSS.MS-PS2-4

The diagram shows a balance being used to find the weight of a baby.

At equilibrium, the pivot is nearer to the 40 N balancing weight than to the baby.

What is the weight of the baby?

• less than 40 N

• 40 N

• more than 40 N

• impossible to tell without a scale on the beam

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

NGSS.MS-PS2-4

A force is a applied to a long crowbar so as to move a large rock.

Which labelled arrow represents the smallest force needed to move the rock?

• A

• B

• C

• D

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

The figure below shows a man lifting a heavy rock using a steel bar. He pushes downwards on the end of the bar with a force F.

Which pivot positions allows the force F to be as small as possible?

• A

• B

• C

• D

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

Which diagram best demonstrates the use of the moment of a force?

• A

• B

• C

• D

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2