F=ma

Q.

A particle is projected with velocity $v_0$ along $x-axis$. A damping force is acting on the particle which is proportional to the square of the distance from the origin i.e. $ma=-\alpha x^2$. The distance at which the particle stops:

1. ${(2v_0/3\alpha )}^{\frac{1}{3}}$

2. ${(3v_0^2/2\alpha )}^{\frac{1}{2}}$

3. ${(3v_0^2/2\alpha )}^{\frac{1}{3}}$

4. ${(2v_0^2/3\alpha )}^{\frac{1}{2}}$

Q.

Define 1 Newton and 1 Dyne.

Q. A bullet makes a clear little hole in a glass, when it hits it, but if we throw a stone at the glass, the whole glass shatters. Why? Which law will you use to support your answer?

Q.

Calculate the force required to accelerate a car from rest to a velocity of $30m{s}^{-1}$ in $10$ seconds. The mass of the car is $1500kg$.

1. $4000N$

2. $3000N$

3. $3500N$

4. $4500N$

Q. Give some examples of Newton's third law of motion.

Q.

Newton's first law of motion defines force.

Q.

A rocket of mass$100kg$ burns $0.1kg$ of fuel per second. If the velocity of exhaust gas is $1km{s}^{-1}$, then it lifts with an acceleration of

1. $1000m{s}^{-2}$

2. $100m{s}^{-2}$

3. $10m{s}^{-2}$

4. $1m{s}^{-2}$

Q.

A body will continue in its state of rest or uniform motion in a straight line, unless acted by some external force. What does this statement represent?

1. Newton's second law of Motion

2. Newton's Law of Gravitation of Motion

3. Newton's first law of motion

4. Law of Conservation of Momentum

Q.

What is the net force acting on an object of mass $10kg$ moving with a uniform velocity of $10m{s}^{-1}$?

1. $15N$

2. $10N$

3. $98N$

4. $0N$

Q.

A student unable to answer a question on Newtons laws of motion attempts to pull himself up by tugging on his hair. He will not succeed

1. as the force exerted is small

2. the frictional force while gripping, is small

3. Newton’s law of inertia is not applicable to living beings

4. as the internal force applied is to the system

Q.

Given radius of earth along the equator is 6378 km and that along the poles is 6357 km. Calculate the percentage change in the weight of a man when he moves from the equator to the poles.

Q.

The product of mass and acceleration is called force.

1. True
2. False

Q.

An object of mass $5kg$is attached to the hook of a spring balance and the balance is suspended vertically from the roof of a lift. The reading on the spring balance when the lift is going up with an acceleration of $0.25m{s}^{-2}$ is taken, (take, $g=10m{s}^{-2}$)

1. $51.25N$

2. $48.75N$

3. $52.75N$

4. $47.25N$

5. $55N$

Q.

The dynamic lift of an airplane is based on

1. Torricelli theorem\

2. Bernoullis theorem

3. Conservation of angular momentum

4. Principle of continuity

Q.

What happens to acceleration when force is constant?

Q.

Does force depend on acceleration?

Q.

Forces $F_1$ and $F_2$act on a point mass in two mutually perpendicular directions. The resultant force on the point mass will be

1. $F_1+F_2$

2. $F_1–F_2$

3. $\sqrt{{F_1}^2+{F_2}^2}$

4. ${F_1}^2+{F_2}^2$

Q. As a rocket is fired from a launch pad, its speed and acceleration increase with time as its engines continue to operate. Explain why this occurs even though the thrust of the engines remains constant.

Q.

When a force F acts on a stationary body for the time t, the distance covered by the body will be proportional to

1. 1/t

2. t

3. t²

4. 1/t²

Q.

Name the principle on which a rocket works.

Q.

State Newton's second law. Prove that Newton's first law of motion is contained in Newton's second law

Q.

Why does a balloon fully inflated with air Rises up vertically for some distance when punctured from below?

Q.

Motion of a rocket can be explained on the basis of Newton's third law.

1. True

2. False

Q. The pressure on a square plate is measured by measuring the force on the plate and the length of the sides of the plate. If the maximum error in the measurement of force and length are respectively 4% and 2%, The maximum error in the measurement of pressure is

1. 1%
2. 2%
3. 6%
4. 8%

Q.

What does mechanical advantage(MA) and virtual reality(VR) mean?

Q. Newton s first law or law of innertia

Q.

A moving body comes to stop without an application of force. Comment.

Q. Two children A and B of same mass (including their caps) M are sitting on a see – saw as chown in figure. Initially, the beam is horizontal. At Once, child B throws away his cap (mass M/25) which falls at point Q, midpoint of the left half of the beam, due to this the balance of beam is disturbed. To balance it again what is the mass m required to be put at point P on the right half of the beam?

1. 0.16M
2. 0.12M
3. 0.04 M
4. 0.1M

Q. Define inertia and momentum.

Q. A submarine can withstand a pressure up to $11\times {10}^{5}Pa$. Find the maximum depth to which the submarine can dive. (Take $1atm={10}^{5}Pa$)

1. 100 m
2. 50 m
3. 75 m
4. 25 m