The diagram shows a 3 . 0 m uniform beam AB, pivoted 1 . 0 m from the end A. The weight of the beam is 200 N . Copy the diagram and mark the beam's centre of mass.

The centre of mass correctly marked,as in the diagram. The Centre of mass of a body or system of a particle is defined as, a point at which the whole of the mass of the body or all the masses of a system of particle appeared to be concentrated. This point is called the centre of mass of the system of particles. The body at this point is balanced and hence no net torque(force) acts on it, thus the body remains in equilibrium.

The diagram shows a 3 . 0 m uniform beam AB, pivoted 1 . 0 m from the end A. The weight of the beam is 200 N . Add arrows to show the following forces: the weight of the beam; the contact forces on the beam at the pivot.

The arrows of the weight of beam and the contact forces on the beam at the pivot is shown in the diagram. The Centre of mass of a body or system of a particle is defined as, a point at which the whole of the mass of the body or all the masses of a system of particle appeared to be concentrated. This point is called the centre of mass of the system of particles. The body at this point is balanced and hence no net torque(force) acts on it, thus the body remains in equilibrium.

The diagram shows a 3 . 0 m uniform beam AB, pivoted 1 . 0 m from the end A. The weight of the beam is 200 N . When the force F is applied, what is the value of the contact force that the pivot exerts on the beam?

From the above diagram, we can conclude that, Upward contact force = sum of downward forces i.e, the weight of the beam = 200 N + 100 N = 300 N . Thus, the contact force that the pivot exerts on the beam is 300 N .

The diagram shows a uniform iron bar B of weight 30 N and length 1 . 40 m . The bar is being used to lift one edge of a concrete slab S . A stone, placed 0 . 20 m from one end of B, acts as a pivot. A force of 40 N pushing down at the other end of B is just enough to lift the slab and hold it as shown. Copy the diagram and draw an arrow to show the weight of bar B acting from its centre of mass.

The downward force arrow at the centre of the bar indicated the centre of mass of the body.

The diagram shows a uniform iron bar B of weight 30 N and length 1 . 40 m . The bar is being used to lift one edge of a concrete slab S . A stone, placed 0 . 20 m from one end of B, acts as a pivot. A force of 40 N pushing down at the other end of B is just enough to lift the slab and hold it as shown. State the distance d of the centre of the mass of bar B from the pivot.

The Centre of mass is at a distance half the length of the beam Centre of mass= 0 . 7 m from the ends. Distance of centre of mass from pivot B = 0 . 7 - 0 . 2 Distance of centre of mass from pivot B = 0 . 5 m .

The diagram shows a uniform iron bar B of weight 30 N and length 1 . 40 m . The bar is being used to lift one edge of a concrete slab S. A stone, placed 0 . 20 m from one end of B, acts as a pivot. A force of 40 N pushing down at the other end of B is just enough to lift the slab and hold it as shown. Suggest a change to the arrangement in the diagram that would reduce the force required to lift the slab.

To reduce the force required to lift the slab in the arrangement in the above diagram, (i) We should make the bar longer or, (ii) Move pivot/stone to the left or, (iii) Move the pivot to left or, increase the mass of the bar or, shift the pivot to the centre of mass.

The sculpture is rotated clockwise to the position shown in the diagram. It is held still, then carefully released. State whether the sculpture will stay in that position, rotate further clock wise or rotate back anticlockwise. Explain you answer to the above condition.

The sculpture stays in that position. It does not change its position due to the equilibrium of forces acting on it. It is due to any of these conditions: clockwise moment = anticlockwise moment. Centre of mass at the pivot. No (resultant) moment/turning force acting on sculpture. Relative distances are from pivot unchanged.

HARD

Upper Secondary: IGCSE

IMPORTANT

Earn 100

Write out step-by-step instructions for an experiment to find the position of the centre of mass of a plane lamina.

Important Questions on Turning Effects of Forces

EASY

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 4 - Turning Effects of Forces>Questions>Q 4.1

Three different forces are shown pulling on a heavy trapdoor. Which force will have the biggest turning effect $?$ Explain your answer.

Question Image

MEDIUM

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 4 - Turning Effects of Forces>End-of-chapter questions>Q 8

The diagram shows a $3.0 m$ uniform beam AB, pivoted $1.0 m$ from the end A. The weight of the beam is $200 N$ .
Question Image
Copy the diagram and mark the beam's centre of mass.

HARD

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 4 - Turning Effects of Forces>End-of-chapter questions>Q 8

The diagram shows a $3.0 m$ uniform beam AB, pivoted $1.0 m$ from the end A. The weight of the beam is $200 N$ .
Question Image
Add arrows to show the following forces: the weight of the beam; the contact forces on the beam at the pivot.

HARD

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 4 - Turning Effects of Forces>End-of-chapter questions>Q 8

The diagram shows a $3.0 m$ uniform beam AB, pivoted $1.0 m$ from the end A. The weight of the beam is $200 N$ .
Question Image
When the force F is applied, what is the value of the contact force that the pivot exerts on the beam?

MEDIUM

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 4 - Turning Effects of Forces>End-of-chapter questions>Q 9

The diagram shows a uniform iron bar B of weight

30 N

and length

1.40 m

. The bar is being used to lift one edge of a concrete slab S . A stone, placed

0.20 m

from one end of B, acts as a pivot.
Question Image

A force of

40 N

pushing down at the other end of B is just enough to lift the slab and hold it as shown.
Copy the diagram and draw an arrow to show the weight of bar B acting from its centre of mass.

HARD

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 4 - Turning Effects of Forces>End-of-chapter questions>Q 9

The diagram shows a uniform iron bar B of weight

30 N

and length

1.40 m

. The bar is being used to lift one edge of a concrete slab S . A stone, placed

0.20 m

from one end of B, acts as a pivot.
Question Image

A force of

40 N

pushing down at the other end of B is just enough to lift the slab and hold it as shown.
State the distance d of the centre of the mass of bar B from the pivot.

HARD

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 4 - Turning Effects of Forces>End-of-chapter questions>Q 9

The diagram shows a uniform iron bar B of weight

30 N

and length

1.40 m

. The bar is being used to lift one edge of a concrete slab S. A stone, placed

0.20 m

from one end of B, acts as a pivot.
Question Image

A force of

40 N

pushing down at the other end of B is just enough to lift the slab and hold it as shown.
Suggest a change to the arrangement in the diagram that would reduce the force required to lift the slab.

HARD

Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 4 - Turning Effects of Forces>End-of-chapter questions>Q 10

The sculpture is rotated clockwise to the position shown in the diagram. It is held still, then carefully released.
Question Image

State whether the sculpture will stay in that position, rotate further clock wise or rotate back anticlockwise. Explain you answer to the above condition.

Write out step-by-step instructions for an experiment to find the position of the centre of mass of a plane lamina.

Important Questions on Turning Effects of Forces

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