Acceleration

Q. A particle moving eastwards with $5{\text{ms}}^{-1}$. In $10\text{s}$ the velocity changes to $5{\text{ms}}^{-1}$ northwards. The average acceleration in this time is

1. $\frac{1}{\sqrt{2}}{\text{m/s}}^2$ North-East.
2. $\frac{1}{2}{\text{m/s}}^2$ North-West.
3. $\frac{1}{\sqrt{2}}{\text{m/s}}^2$ North-West.
4. Zero.

Q.

Define resultant vector.

Q.

The motion of a particle is described by the equation $x=a+b{t}^2$, where $a=15cm$ and $b=3cm/s^2$. Its instantaneous velocity at a time $3$ sec will be.

1. $36cm/sec$

2. $18cm/sec$

3. $16cm/sec$

4. $32cm/sec$

Q. The motion of a body is given by the equation $\frac{dv}{dt}=6-3v$, where $v$ is speed in $m/s$ and $t$ is time in seconds. If the body is at rest at $t=0$, then

1. the terminal speed is $2m/s$.
2. the speed varies with the time as $v=2(1-e^{-3t})m/s$.
3. the speed is $0.1m/s$ when the acceleration is half the initial value.
4. the magnitude of the initial acceleration is $6m/s^2$.

Q.

Find the gravitational potential energy of a system of four particles, each having mass m, placed at the vertices of a square of side l at the centre of the square.

1. 

2. 

3. 

4. zero

Q. Assertion: A body can have an acceleration even if its velocity is zero at a given instant of time.
Reason: A body is momentarily at rest when it reverses its direction of motion.

1. If both Assertion and Reason are true and the Reason is correct explanation of the Assertion
2. If both Assertion and Reason are true, but Reason is not correct explanation of the Assertion
3. The Assertion is true, but the Reason is false
4. The Assertion is false and Reason is true

Q.

Two identical blocks P and Q have mass ‘m’ each. They are attached to two identical springs initially unstretched. Now the left spring (along with P) is compressed by $\frac{A}{2}$ and the right spring (along with Q) is compressed by A. Both the blocks are released simultaneously. They collide perfectly inelastically. Initial time period of both the blocks was T. [consider k as spring constant of each spring]

The time period and amplitude of oscillation of the combined mass is respectively,

1. $\frac{T}{\sqrt{2}}$ and $\frac{A}{4}$

2. $T$ and $\frac{A}{4}$

3. $\frac{T}{2}$ and $\frac{A}{2}$

4. $\frac{T}{2}$ and $\frac{A}{4}$

Q.

A player caught a cricket ball of mass 150 gm moving at a rate of 20 m/s. If the catching process be completed in 0.1 s, then the force of the blow exerted by the ball on the hands of the player is

1. 0.3 N

2. 30 N

3. 3000 N

4. 300 N

Q. A block of mass $m$ slides down an inclined plane of inclination $\theta$ with uniform speed. The coefficient of friction between the block and the plane is $\mu$. The contact force between the block and the plane is

1. $\sqrt{(\text{mg sin}\theta {)}^2+(\mu \text{mg cos}\theta {)}^2}$
2. $\text{mg sin}\theta \sqrt{1+{\mu }^2}$
3. $\text{mg sin}\theta$
4. $\text{mg}$

Q.

List some examples of acceleration.

Q.

Draw a velocity versus time graph of a stone thrown vertically upwards and then coming downwards after attaining the maximum height.

Q. The displacement $x$ of a particle along a straight line at time $t$ is given by $x=a_0-a_{1}t+a_2{t}^2$. The acceleration of the particle is

1. $a_0$
2. $a_1$
3. $2a_2$
4. $a_2$

Q. A block of mass 10kg is released on rough inclined plane. Block start descending with acceleration 2m/s. Kinetic force acting on block is? Angle of inclination is 30^°

Q. A particle executing SHM has acceleration 12cm/s^2 at 3 cm from its mean position. Time period of particle is

Q. A particle is moving in the $x-y$ plane. At certain instant of time, the components of its velocity and acceleration are as follows: $v_x=3{\text{ms}}^{-1},v_y=4{\text{ms}}^{-1},a_x=2{\text{ms}}^{-2}$ and $a_y=1{\text{ms}}^{-2}$. The rate of change of speed at this moment is

1. $\sqrt{10}{\text{ms}}^{-2}$
2. $4{\text{ms}}^{-2}$
3. $\sqrt{5}{\text{ms}}^{-2}$
4. $2{\text{ms}}^{-2}$

Q.

What is negative acceleration?

Q.

The displacement $x$ of a particle at time $t$ along a straight line is given by $x=\alpha -\beta t+\gamma t^2$. Find the acceleration of the particle.

Q.

A particle is at rest at t = 0. If acceleration of the particle is given as $a=sin\pi t+cos\pi t$ in unit then the maximum speed of the particle is

Q. What does the slope of position-time graph represent?

Q. $P,Q$ and $R$ are three coplanar forces acting at a point and are in equilibrium. Given $P=1.9381kgwt.,\sin {\theta }_1=0.9659,$ the value of $R$ is (in $kgwt.)$

Q. In solar cell, why $GaAs$ preferred over $Si$?

1. Because $GaAs$ is cheap.
2. Because $GaA$ is abundant is nature.
3. Because $GaAs$ bandgap is lower than $Si$ bandgap.
4. Because $GaAs$ has better absorptive nature than $Si$.

Q. Derivation for acceleration due to gravity on its effects of height and depth... Explain plllzzz

Q. A balloon initially at rest start rising with constant acceleration of $10{\text{m/s}}^2$. After $2\text{s}$ a particle drops from the balloon. After further $2\text{s}$, match the following (Take $g=10{\text{m/s}}^2$ )
$\begin{array}{cc}\text{Table-1}& \text{Table-2}\\ \text{(A) Height of particle from ground is}& \text{(P) Zero}\\ \text{(B) Speed of particle is}& \text{(Q) 10 SI units}\\ \text{(C) Displacement of particle is}& \text{(R) 40 SI units}\\ \text{(D) Acceleration of particle is}& \text{(S) 20 SI units}\end{array}$

1. $\left(A\right)\to \left(R\right);\left(B\right)\to \left(P\right);\left(C\right)\to \left(S\right);\left(D\right)\to \left(Q\right)$
2. $\left(A\right)\to \left(R\right);\left(B\right)\to \left(Q\right);\left(C\right)\to \left(P\right);\left(D\right)\to \left(S\right)$
3. $\left(A\right)\to \left(S\right);\left(B\right)\to \left(P\right);\left(C\right)\to \left(R\right);\left(D\right)\to \left(Q\right)$
4. $\left(A\right)\to \left(S\right);\left(B\right)\to \left(Q\right);\left(C\right)\to \left(R\right);\left(D\right)\to \left(P\right)$

Q.

A person standing on the top of a cliff, 171 ft high, has to throw a packet to his friend standing on the ground 228 ft horizontally away. If he throws the packet directly aiming at the friend with a speed of 15.0 ft/s, how short will the packet fall? Give g = 32 ft/s2.

Q.

Torque acting on a current carrying coil is maximum when :

1. Magnetic moment is parallel to the area vector

2. Magnetic moment is parallel to the magnetic field.

3. Magnetic moment is perpendicular to the area vector

4. None of the above

Q.

What do you mean by acceleration ? State its CGS and SI units .

Q. In non inertial frame, the second law of motion is written as where For is pseudo force while a is the acceleration of the body relative to non inertial frame.). (1) F=ma. (2) F=ma+Fp. (3)F=ma-Fp. (4) F=2ma

Q. A point moves rectilinearly with deceleration which depends on the velocity $v$ of the particle as $a=k\sqrt{v}$, where $k$ is a positive constant. At the initial moment the velocity of the point is equal to $v_0$. What distance will it cover before it stops ?

1. $\frac{3v_0^{\frac{3}{2}}}{2k}$
2. $\frac{v_0^{\frac{1}{2}}}{2k}$
3. $\frac{v_0^{\frac{3}{2}}}{3k}$
4. $\frac{2v_0^{\frac{3}{2}}}{3k}$

Q.

Is velocity at the highest point zero

Q.

A bullet of mass 5g is shot from a gun of mass 5kg . The muzzle velocity of the bullet is 500m/s .What is the recoil velocity of the gun?