Advertisements
Advertisements
Question
Two forces each of magnitude 10 N act vertically upwards and downwards respectively at the two ends A and B of a uniform rod of length 4 m which is pivoted at its midpoint O as shown in the figure. Determine the magnitude of the resultant moment of forces about the pivot O.

Advertisements
Solution
F = 10 N on each side
distance of each force from O = 2m
Both are clockwise moments
i.e. 10 N × 2m + 10 N × 2m
= 20 N m + 20 N m
= 40 N m
APPEARS IN
RELATED QUESTIONS
Moment of force = force × perpendicular distance of force – from the pivoted point.
Match the column
| Column A | Column B |
| (a) Camel | (1) broad and deep foundation |
| (b) Truck | (2) broad feet |
| (c) Knife | (3) six or eight tyres |
| (d) High building | (4) sharp cutting edge |
| (e) Thrust | (5) atm |
| (f) Moment of force | (6) N |
| (g) Atmospheric pressure | (7) N m |
State the effect of force F in of the following diagram.

A potter turns his wheel by applying a force through the stick near the rim of wheel.
State the relationship between force, mass and acceleration. Draw graphs showing the relationship between Acceleration and force for a constant mass.
Write the expression for calculating the moment of force about a given axis.
The diagram shows two forces F1 = 5 N and F2 = 3N acting at point A and B of a rod pivoted at a point O, such that OA = 2m and OB = 4m

Calculate:
- Moment of force F1 about O
- Moment of force F2 about O
- Total moment of the two forces about O.
One joule is the amount of work done when a force of ......... moves a body through a distance of .......
What is meant by the term ‘moment of force’? If the moment of force is assigned a negative sign then will the turning tendency of the force be clockwise or anti-clockwise?
A person standing in front of a cliff fires a gun and hears its echo after 3 s. If the speed of sound in air is 336 ms−1.
- Calculate the distance of the person from the cliff.
- After moving a certain distance from the cliff, he fires the gun again, and this time the echo is heard 1.5 s later than the first. Calculate the distance that the person moved.
