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 . A third force F presses down on the beam (at endpoint A). What value of F is needed to balance the beam?

As the third force F is applied at endpoint A. Moment of weight = force × distance = 200 × 0 . 5 = 100 Nm . The force F needed to balance the beam is equal to the weight of the body so F = 100 N .

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 .

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Upper Secondary: IGCSE

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What quantity is a measure of the turning effect of a force?

Important Questions on Turning Effects of Forces

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Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 4 - Turning Effects of Forces>End-of-chapter questions>Q 6

What two conditions must be met if an object is to be in equilibrium?

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Upper Secondary: IGCSE

IMPORTANT

Cambridge IGCSE® Physics Coursebook Second Edition>Chapter 4 - Turning Effects of Forces>End-of-chapter questions>Q 7

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

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Upper Secondary: IGCSE

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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.

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
A third force F presses down on the beam (at endpoint A). What value of F is needed to balance the beam?

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.

What quantity is a measure of the turning effect of a force?

Important Questions on Turning Effects of Forces

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