The people in a bus are pushed backwards when the bus starts suddenly because of:
When the bus is not moving the passengers are in the state of rest and they have inertia of rest. When the bus starts moving suddenly, the lower part of the body of passengers, which is in contact with the bus, come in motion, but upper part of their body tends to be in the state of rest and the passengers fall backward.
Between a football and stone of same size, the inertia of:
Inertia of stone is greater than the inertia of football because mass of stone is higher than the mass of football even both are of same size.
A cyclist of mass 30 kg exerts a force of 250 N to move his cycle. The acceleration is 4 ms−2. The force of friction between the road and tyres will be
Force - force of friction = mass × acceleration
250 - f = 30 × 4
f = 250 - 120
While dusting a carpet we beat it with a stick because:
When a hanging carpet is beaten with a stick, the dust particles are removed from it because the carpet on beating suddenly moves forward and the dust particles due to inertia of rest continue to remain at rest. Hence the dust particles fall down and the carpet gets cleaned.
If no external force acts on a moving object:
If an object is moving at a constant speed or velocity, it will continue at that speedunless acted upon by some force along the line of motion. If an object is moving, itwill move in a straight line unless acted upon at an angle by some force.