Acceleration

Q.

The distance travelled by a body is directly proportional to the time taken. Its speed.

1. increases

2. decreases

3. becomes zero

4. remains constant

Q.

SI unit of acceleration is:

1. kmph

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

3. m

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

Q.

A body starting from rest is moving with an uniform acceleration of 8m/s^2.Then the distance travelled by it in 5th second will be....

Q. 49.a coil having uniform magnetic moment 15 Am2 placed in auniform magnetic field of 2T in the horizontal direction exists such that initially the axis of the coil is in the direction of the field .if the coil is rotated by45 and the moment of inertia of the coil is 0.5 kgm2 then the angular speed aquired by the coil is

Q. 3. a stone of mass m gram is rotated in a circular path with a uniform speed by tieing a strong string with the help of your hand ? answer the following:-
i)is the stone moving with uniform or variable speed
ii)is the stone moving a uniform acceleration or variable accelertion? in which direction the acceleraton act?

Q. Which of the following is not a vector quantity?

1. Acceleration
2. Velocity
3. Speed
4. Displacement

Q. An object is moving in a straight-line path has a velocity of $40\text{m/s}$ at some instant. After $5\text{s}$, its velocity changed to $30\text{m/s}$. What is the average acceleration of the ball during this time interval?

1. $-2{\text{m/s}}^2$
2. $-4{\text{m/s}}^2$
3. $2{\text{m/s}}^2$
4. $4{\text{m/s}}^2$

Q. In a block and tackle system consisting of $3$ pulleys, a load of $75kgf$ is raised with an effort of $25kgf$Find the efficiency?

1. $100\%$
2. $10\%$
3. $200\%$
4. $500\%$

Q. The acceleration of a car moving in positive $x-$direction with an initial velocity of $6m/s$ is $4m/s^2$. Its velocity at $t=5sec$ is

1. $26m/s$
2. $24m/s$
3. $28m/s$
4. $22m/s$

Q. 110. As shown in the figure, a three-sided frame is pivoted { at P and Q and hangs vertically. Its sides are of same { length and have a linear density of \sqrt3kg/m . A current { of 10\sqrt3A is sent through the frame, which is in a { uniform magnetic field of 2T directed upwards as shown. Then angle through which the frame will be deflected in equilibrium is: { (Take g=10m/s^2)

Q. Rahul and Rohan live on two different floors of the same building. If they drop a ball from their balconies at the same time, what would be the difference in their accelerations after 1 s?

Q.

An object is moving in a straight-line path has a velocity of $40\text{m/s}$ at some instant. After $10\text{s}$, its velocity changed to $80\text{m/s}$. What is the average acceleration of the ball during this time interval?

1. $10{\text{m/s}}^2$
2. $2{\text{m/s}}^2$
3. $6{\text{m/s}}^2$
4. $4{\text{m/s}}^2$

Q. A body dropped from rest at tuop of the tower falls 1/2 of its total distance in last second of fall. Find time of flight and total height of tower.

Q. In motion of a simple pendulum acceleration and kinetic energy are maximum at ..............

1. $C,B,A$
2. $A,B,C$
3. $A$ only
4. $B,C$ only

Q.

An object of mass 1 kg was moving at a speed of $10\frac{m}{s}$. A constant force acts for 4s on the object and the speed of object was $2\frac{m}{s}$ in opposite direction after the applied force was removed. The force acting on the object was:

1. 3N

2. -3N

3. 30N

4. -30N

Q.

Q: What is mean by acceleration mean?

Q. A man whose mass is $mkg$ jumps vertically into air from the sitting position in which his centre of mass is at a height $h_1$ from the ground. When his feet are just about to level the ground his center of mass is at height $h_2$ from the ground and finally center of mass rises to $h_3$ above the ground when he is at the top of the jump. What is the average upward force exerted by the ground on him?

1. $\frac{mg(h_3-h_1)}{(h_3-h_2)}$
2. $\frac{mg(h_3-h_1)}{h_3}$
3. $\frac{mg(h_3-h_1)}{(h_2-h_1)}$
4. none of these

Q. The velocity components of a particle moving in the xy plane of the reference frame $K$ are equal to $v_x$ and $v_y$. Find the velocity $v^{\prime }$ of this particle in the frame $K^{\prime }$ which moves with the velocity $V$ relative to the frame $K$ in the positive direction of its x axis.

Q. The second equation of motion in rotatory motion is

1. $S=ut+\frac{a{t}^2}{2}$
2. $\theta ={\omega }_{1}t+\frac{\alpha t^2}{2}$
3. ${\omega }_2^2={\omega }_1^2+2\alpha \theta$
4. ${\omega }_2={\omega }_1+\alpha t$

Q. Assertion :If a particle projected horizontally just above the surface of the earth with a speed greater than escape speed, then it will escape from gravitational influence of the earth. Assume that particle has a clear path. Reason: Escape velocity is independent of its direction.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect and Reason is correct

Q. A satellite is launched into an orbit around the Earth. It has a critical velocity of about $6{\text{km s}}^{-1}$. What is the height of the satellite in $\text{km}$? ($\text{G}=6.67\times {10}^{-11}{\text{Nm}}^2{\text{kg}}^{-2}$, $\text{M}=6\times {10}^{24}\text{kg}$, and $\text{R}=6,370\text{km}$)

1. 4745.67

Q. A satellite is launched into an orbit around the Earth. It has a critical velocity of about $6{\text{km s}}^{-1}$. What is the height of the satellite in $\text{km}$? ($\text{G}=6.67\times {10}^{-11}{\text{Nm}}^2{\text{kg}}^{-2}$, $\text{M}=6\times {10}^{24}\text{kg}$, and $\text{R}=6,370\text{km}$)

1. $5,875\text{km}$
2. $4,746\text{km}$
3. $3,320\text{km}$
4. $8,684\text{km}$

Q. For an object moving in a circular path, the centripetal force acts on it towards the centre of the path.

1. False
2. True

Q. If the acceleration due to gravity is $10m^{-2}$ and the units of length and times are changes in kilometer and hour respectively. The numerical value of the acceleration is

1. $360000$
2. $72000$
3. $36000$
4. $129600$