Linear Momentum

Q.

Is linear momentum of a system always conserved?

Q.

A particle of mass m moving with velocity v strikes a stationary particle of mass 2m and sticks to it. The speed of the system will be

1. 2v

2. 

3. 

4. 3v

Q.

A uranium-238 nucleus, initially at rest, emits an alpha particle with a speed of $1.4\times {10}^7$ $m/s$.Calculate the recoil speed of the residual nucleus thorium-234.Assume that the mass of a nucleus is proportional to the mass number.+

Q.

A stationary particle explodes into two particles of masses x and y which move in opposite directions with velocity v1 and v2. The ratio of their kinetic energy is

Q.

Why does the recoil of a heavy gun on firing not so strong as of light gun using the same cartidge?

Q. The ball is thrown vertically up (taken $+z-$ axis) from the ground. The correct momentum-height $(p-h)$ diagram is:

1. 
2. 
3. 
4. 

Q.

$10,000$ small balls, each weighing $1g$ strike one square $cm$ of area per second with a velocity of $100m{s}^{-1}$ in a normal direction and rebound with the same velocity. The value of pressure on the surface will be

1. $2x{10}^{3}N{m}^{-2}$

2. $2x{10}^{5}N{m}^{-2}$

3. ${10}^{7}N{m}^{-2}$

4. $2x{10}^{7}N{m}^{-2}$

Q.

A man standing on a boat in still water. If he walks towards the shore the boat will

1. move away from the shore

2. remain stationary

3. move towards the shore:

4. sink

Q. The magnetic flux linked with a loop changes with time according to the equation, $\varphi =a{t}^2+bt+c$ where $t$ is time in $\text{s}$ and $a,b$ and $c$ are constants. The SI unit of $a$ is

1. $\text{V}$
2. $\frac{\text{V}}{\text{s}}$
3. $\text{V - s}$
4. $\text{Wb}$

Q.

When two objects collide, then their total momentum before and after collision remains:

1. zero

2. conserved

3. fixed

4. any of these

Q. A projectile is fired at ${30}^{\circ }$ with momentum p. Neglecting friction, the change in kinetic energy when it returns to the ground will be

1. 
2. 
3. 
4. 

Q. What is law of conservation of angular and linear momentum?

Q.

If a moving ball A collides with another moving ball B, then

1. Momentum of A = Momentum of B

2. (Momentum of A+ momentum of B) before collision = (Momentum of A+ momentum of B) after collision

3. neither (a) nor (b)

4. Both (a) and (b)

Q.

Find the ratio of the linear momenta of two particles of masses 1.0 kg and 4.0 kg if their kinetic energies are equal.

Q.

The law of conservation of momentum states that the sum of momenta of two objects before the collision is equal to the sum of momenta after the collision provided that ________________.

Q.

A body of mass $5kg$ undergoes a change in speed from $20m{s}^{-1}$to $0.20m{s}^{-1}$. The momentum :

1. increases by $99kgm{s}^{-1}$

2. decreases by $99kgm{s}^{-1}$

3. increases by $101kgm{s}^{-1}$

4. decreases by $101kgm{s}^{-1}$

Q.

A jet engine works on the principle of conservation of

1. Mass

2. Energy

3. Flow

4. Linear momentum

Q.

If no external force acts on a body, its momentum remains ----

Q.

What will be the momentum of a body of mass $0.5kg$ moving with a speed of $10\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s$}\right.$.

Q.

What is the principle of conservation of momentum?

Q. State law of conservation of linear momentum?

Q. Two identical blocks are resting on supports as shown. Two identical bullets travelling with the same speed hit the blocks & get embedded in them in very short time. The blocks leave the contact immediately after bullet strikes them. In case (i), bullet's velocity is toward centre of mass and in case (ii), bullet's velocity is off centre. The kinetic energies after collision are $K_1$ & $K_2$ and maximum height reached by the centre of mass are $h_1$ & $h_2$ respectively. Then

1. $K_1<K_2$
2. $K_1=K_2$
3. $h_1>h_2$
4. $h_1=h_2$

Q.

Which has a higher value of momentum? A bullet of mass $10g$ moving with a velocity of $400m{s}^{-1}$ or a cricket ball of mass $400g$ thrown with the speed of $90km{h}^{-1}$.

Q. A ball is thrown vertically up (taken as + z - axis) from the ground. The correct momentum - height (p - h) diagram is:(Given p=mv)

1. 
2. 
3. 
4. 

Q. Which of the following statements is not correct regarding conservation laws?

1. A conservation law is a hypothesis based on observations and experiments
2. Conservation laws do not have a deep connection with symmetries of nature.
3. A conservation law cannot be proved.
4. Conservation of energy, linear momentum, angular momentum are considered to be fundamental laws of physics.

Q. A massless spring attached to a rigid support at one end and a mass m at other end is placed on smooth surface. The mass is pulled and released. It executes SHM with time period T. If time period for given systems is given by T'. Then match the following. (Given that in part d energy gets lost, but consider only spring force for calculating time period)

1. A-s, b-q, c-p, d-r
2. A-s, b-p, c-q, d-r
3. A-r, b-q, c-p, d-r
4. A-s, b-q, c-r, d-p

Q. what are fundamental laws of nature and why conservation of mass and energy not consideredas fundamental laws of nature

Q.

$10,000$ small balls, each weighing $1g$ strike one square $cm$ of area per second with a velocity of $100m{s}^{-1}$ in a normal direction and rebound with the same velocity. The value of pressure on the surface will be

1. $2\times {10}^{3}N{m}^{-2}$

2. $2\times {10}^{5}N{m}^{-2}$

3. ${10}^{7}N{m}^{-2}$

4. $2\times {10}^{7}N{m}^{-2}$

Q. State the law of conservation of momentum and derive related expression.

Q. State and explain the how of conservation of linear momentum