Centre of Gravity

Q.

A metre stick is balanced on a knife edge at its centre. When two coins, each of mass 5 g are put one on top of the other at the 12.0 cm mark, the stick is found to be balanced at 45.0 cm. What is the mass of the metre stick?

Q.

From a uniform disk of radius R, a circular hole of radius R/2 is cut out. The centre of the hole is at R/2 from the centre of the original disc. Locate the centre of gravity of the resulting flat body.

Q.

A non-uniform bar of weight W is suspended at rest by two strings of negligible weight as shown in Fig.7.39. The angles made by the strings with the vertical are ${36.9}^{\circ }$ and ${53.1}^{\circ }$ respectively. The bar is 2 m long. Calculate the distance d of the centre of gravity of the bar from its left end.

Q.

A car weighs 1800 kg. The distance between its front and back axles is 1.8 m. Its centre of gravity is 1.05 m behind the front axle. Determine the force exerted by the level ground on each front wheel and each back wheel.

Q.

The point at which the entire weight of a body is assumed to be concentrated is known as ___.

1. centre of torque

2. centre of mass

3. centre of velocity

4. centre of gravity

Q.

The centre of gravity of an uniform circular ring lies ________.

1. at one end of the diameter of the ring

2. outside the ring

3. at centre of the ring

4. on the circumference of the ring

Q.

What is the center of gravity of an object?

1. It is the point at which weight is evenly dispersed and all sides are in balance.

2. It is the point at which density is evenly dispersed and all sides are in balance.

3. It is the point at which weight is randomly dispersed and all sides are in balance.

4. It is the point at which weight is evenly dispersed and all sides are not in balance.

Q.

Tightrope walkers use _________ to balance their weight.

1. metallic sphere

2. metallic disc

3. metallic ring

4. long cane

Q.

A ruler scale is balanced with two fingers, $F_1$ and $F_2$ at a separation 20 cm and 40 cm from the centre of the scale O respectively. If the person balancing the ruler tries to bring his fingers closer to the centre, which finger will slide first?

1. Insufficient data

2. Both simultaneously

3. $F_1$

4. $F_2$

Q.

A square plate of side 4 metre has uniform mass density and is hinged at the midpoint of one of its edge as shown in the figure. What will be the torque due to gravity on it about the hinged point A? (Mass of the plate = $20kg$; g = $10m{s}^2$)

1. 200 N-m

2. 100 N-m

3. 400 N-m

4. 300 N-m