Question 1:
easy
A passenger in the bus finds that his suit-case suddenly starts sliding backwards. This means that the bus is :
This is due to inertia of motion.
Question 2:
easy
Passengers standing in a bus are thrown outwards when the bus takes a sudden turn. This happens because of :
Due to inertia of direction person inside the bus has a tendency to move in a straight line. In case of sudden turn body ties to maintain its linear motion.
Question 3:
easy
Generally it is said “Normal reaction always acts perpendicular to the surface of contact” :
Normal reaction force is always normal ( Perpendicular ) to the surface.
Question 4:
easy
In the motion picture ‘It happened one night’ (columbia pictures, 1934), Clark ceable in
standing inside a stationary bus in front of the claudetle colbert, who is seated, the bus suddenly starts moving forward and clark fall into claudetters lap which of following explains this phenomena best :
Due to inertia of rest clark want to remain at rest.
Question 5:
easy
A large force \(f\) acts on a particle of mass \(m\) for a short time \(t\). The impulse imparted to the particle is given by
Impulse is defined as the product of the average force and the short time interval over which it acts, i.e., \(\text{Impulse} = f \times t\).
Question 6:
easy
A ball of mass \(0.15\text{ kg}\) is dropped from a height \(10\text{ m}\), strikes the ground and rebounds to the same height. The magnitude of impulse imparted to the ball is (\(g = 10\text{ m/s}^2\)) nearly
The velocity of the ball just before striking the ground is \(u = \sqrt{2gh} = \sqrt{2 \times 10 \times 10} = 14.14\text{ m/s}\). Since it rebounds to the same height, its velocity just after is \(v = 14.14\text{ m/s}\) upwards. The change in momentum is \(Delta p = m(v - (-u)) = 2mu = 2 \times 0.15 \times 14.14 \approx 4.24\text{ kg m/s}\).
Question 7:
easy
An object of mass 2 kg is placed on a smooth horizontal surface. A water jet throws water at a rate of 2 kg/s with speed 20 m/s which strikes the object horizontally. The force applied by water jet and acceleration of the object respectively, are
Formula: \(F = v \frac{dm}{dt} = 20 \times 2 = 40\text{ N}\). Using Newton's second law, acceleration \(a = \frac{F}{m} = \frac{40}{2} = 20\text{ m/s}^2\).
Question 8:
easy
A player catches a ball of mass \(150\text{ g}\) in \(0.1\text{ s}\) moving with speed \(20\text{ m/s}\), then he experiences an average force of
By Newton's second law, \(F = \frac{\Delta p}{\Delta t} = \frac{mv}{t}\). Substituting the values, \(F = \frac{0.15\text{ kg} \times 20\text{ m/s}}{0.1\text{ s}} = 30\text{ N}\).
Question 9:
easy
If a cloth covers a table and some dishes are kept on it, then the cloth can be pulled out without dislodging the dishes from the table by pulling the cloth suddenly. The dishes will remain on table due to
According to Newton's First Law, when the cloth is suddenly pulled, the dishes tend to maintain their state of rest due to the inertia of rest.
Question 10:
easy
Assertion (A): If a particle is found to be in equilibrium in two different frames of reference implies that both frames are inertial.
Reason (R): Newton’s second law can be used for motion of a particle in any reference frame.
Assertion (A) is false. Two non-inertial frames accelerating identically relative to an inertial frame could both observe a particle in equilibrium. Reason (R) is false. Newton's second law \( \vec{F} = m \vec{a} \) strictly applies in inertial frames; pseudo forces must be included in non-inertial frames. Therefore, both (A) and (R) are false.