Explanation

When a body is in unstable equilibrium, a slight tilt will cause its center of gravity (CG) to remain above the point of contact, making it prone to toppling over or falling.

This means that the CG is not directly over the point of support, but is still above it, creating a moment that tends to rotate the body further.

Key Points:

• A body is in stable equilibrium after slight tilt if its center of gravity remains above the point of contact.
• A body is in neutral equilibrium when its center of gravity remains at same height.

Explanation

When a body is tilted slightly, if its center of gravity remains above the point of contact, it will tend to return to its original position, restoring equilibrium.

This is a characteristic of stable equilibrium.

Key Points:

• A body is in unstable equilibrium after slight tilt if its center of gravity remains above the point of contact.
• A body is in neutral equilibrium when its center of gravity remains at same height.

Explanation

A body is in equilibrium when the net force acting on it is zero, and it is not changing its motion.

This means that the body is either at rest or moving with a constant velocity (uniform speed), but not accelerating.

Explanation

The vertical component of the force is:

Vertical component = Force × sin(angle)

= 15 N × sin(60°)

= 15 N × 0.866

= 13 N

So, the vertical component of the 15 N force at an angle of 60° is approximately 13 N.

Explanation

The head-to-tail rule is a method for adding vectors, such as forces, by lining up the head of one vector with the tail of the next vector.

This rule can be used to add any number of forces, not just two or three.

Explanation

• A pair of unlike parallel forces (forces that act in opposite directions) with different lines of force produce a couple.
• It is also known as a moment or torque.
• This is a rotational force that tends to cause rotation around a pivot point or axis.

Explanation

To find the acceleration of the sledge, we can use Newton's second law of motion: F = ma, where F is the net force acting on the sledge, m is its mass, and a is its acceleration.

First, we need to find the net force acting on the sledge. The force applied by the man is 60 N, and the force of friction is 20 N, so the net force is:

F = 60 N - 20 N = 40 N

Next, we can plug in the values to Newton's second law:

40 N = (25 kg) × a

To find the acceleration, we can divide both sides by the mass:

a = 40 N / 25 kg = 1.6 ms^-2

Therefore, the acceleration of the sledge is 1.6 ms^-2.

Explanation

Limiting frictional force (also known as static friction) is greater than:

• Rolling friction (because rolling friction is much smaller, as it only opposes the motion of an object that is already rolling)
• Sliding friction (which is another term for kinetic friction)
• Kinetic friction (which is the frictional force that acts when an object is already moving)

Explanation

• Friction is a force that opposes motion between two bodies in contact, and it arises due to the interaction between the surfaces in contact.
• The roughness of the surfaces, including microscopic imperfections and irregularities, leads to interlocking and resistance to motion.
• This resistance is what we experience as friction.

Explanation

Centrifugal force is a fictitious force that appears to act on an object moving in a circular path, causing it to move away from the center of the circle.

It is a result of the inertia of the object, which tends to keep it moving in a straight line.