Mass vs Weight

Q.

An uniform wooden beam AB, 80 cm long and weighing 250 gf, is supported on a wedge as shown in Fig. below calculate the greatest weight which can be placed on end A without causing the beam to tilt.

Q. A man is inside a lift. When the lift is moving up with certain acceleration, the apparent change in weight is $25\%$. When the lift moves down with double the acceleration, the apparent change in weight is

1. $25\%$
2. $50\%$
3. $75\%$
4. $40\%$

Q. In the figure shown, with what force must the man pull the rope to hold the plank in position? Weight of the man is 80 kg-f. Neglect the weights of plank, ropes and pulleys.

1. 80 kg-f
2. 20 kg-f
3. 50 kg-f
4. 40 kg-f

Q.

An inclined plane is also called _____.

Q.

A block of mass M is resting on an inclined plane as shown in the figure. The inclination of the plane to the horizontal is gradually increased. It is found that when the angle of inclination is $\theta$, the block just begins to the slide down the plane. What is the minimum force F applied parallel to the plane that would just make the block move up the plane?

1. $Mgsin\theta$

2. $Mgcos\theta$

3. $2Mgcos\theta$

4. $2Mgsin\theta$

Q. A body of mass $100\text{g}$ is at rest on a smooth surface. A force of $0.1\text{N}$ starts to act on it for $5\text{s}$. Calculate the distance travelled by the body during this time interval.

1. $12.5\text{m}$
2. $25.5\text{m}$
3. $15.5\text{m}$
4. $35.5\text{m}$

Q. A man of mass $m$ is standing on weighing machine in an elevator accelerating upwards with an acceleration $a$. What will be the reading of weighing machine?

1. $m(g-a)\text{N}$
2. $m(g+a)\text{N}$
3. $\frac{m}{(g-a)}\text{N}$
4. $\frac{m}{(g+a)}\text{N}$

Q. The beam and pans of a balance have negligible mass. An object weighs $W_1$ when placed in one pan and $W_2$ when placed in the other pan. The true weight $W$, of the object is

1. $\sqrt{W_1{W}_2}$
2. $\sqrt{(W_1+W_2})$
3. $W_1^2+W_2^2$
4. $(W_1^{-1}+W_2^{-1})/2$

Q.

Three weights W, 2W and 3W are connected to identical springs suspended from a rigid horizontal rod. The assembly of the rod and the weights fall freely. The positions of the weights from the rod are such that

1. 3W will be farthest

2. W will be farthest

3. All will be at the same distance

4. 2W will be farthest

Q. Find the reading (in $\text{newtons}$) of spring balance when system shown in the figure below is released from rest. $($Take $g=10\text{m/}{s}^2)$

1. $300\text{N}$
2. $\frac{200}{3}\text{N}$
3. $\frac{400}{3}\text{N}$
4. $\frac{800}{3}\text{N}$

Q. A rod AB of weight $W_1$ is placed over a sphere of weight $W_2$ as shown in the figure. If friction is absent, the number of forces to be shown on the sphere in its FBD is/are?

1. 3
2. 4
3. 6
4. 5

Q. Name the physical quantity which causes motion in a body.

1. Force
2. Energy
3. Work
4. Power

Q.

A car of mass $200kg$is accelerating under the action of a force $F=3000N$as shown in figure. A block of mass $3kg$is at rest on the surface of car. $[3kgisincludedin200kg]$. Determine the net force acting on the $3kg$ mass.

Q.

A man of mass M stands on a weighing machine in an elevator accelerating upwards with an acceleration $a_0$ . Calculate the reading of the weighing machine

1. Mg

2. M(g+a)

3. M(g-a)

4. Zero

Q.
A solid sphere and a spherical shell with same mass and same radius but with opposite charge are released from rest on a rough surface which is sufficient to avoide sliding. Our system consists of the solid sphere and the shell. Mark the correct statements for the above system.

1. Mechanical energy of the system is conserved.
2. Linear momentum of the system is conserved.
3. Angular momentum of the system is not conserved about any point.
4. Center of mass will displace.

Q.

The relation between force, mass and acceleration is

1. $F=ma$

2. $m=Fa$

3. $a=mF$

4. $mFa=1$

Q.

A man of mass M stands on a weighing machine in an elevator accelerating upwards with an acceleration $a_0$ . Calculate the reading of the weighing machine

1. 

2. 

3. 0, the body won't move

4. 

Q. Three weights W, 2W and 2W are connected to identical springs suspended form rigid lkhorizontal rod. The assembly of the rod and the weights fall freely. The positions of the weights from the rod are such that

1. 3W will be farthest
2. W will be farthest
3. All will be at the same distance
4. 2 W will be farthest

Q. A false balance has equal arms. An object weighs $\text{X}$ when placed in one pan and $\text{Y}$ when placed in other pan. Then the weight $\text{W}$ of the object is equal to

1. $\frac{X^2+Y^2}{2}$
   
2. $\frac{X+Y}{2}$
   
3. $\frac{2}{\sqrt{X^2+Y^2}}$
   
4. $\sqrt{XY}$
   

Q.

A block of mass M is resting on an inclined plane as shown in the figure. The inclination of the plane to the horizontal is gradually increased. It is found that when the angle of inclination is $\theta$, the block just begins to the slide down the plane. What is the minimum force F applied parallel to the plane that would just make the block move up the plane?

1. $Mgsin\theta$

2. $Mgcos\theta$

3. $2Mgcos\theta$

4. $2Mgsin\theta$

Q. A solid sphere with a velocity (of centre of mass) $v$ and angular velocity $\omega$ is gently placed on a rough horizontal surface. The frictional force on the sphere :

1. must be forward (in direction of $v$)
2. must be backward (opposite to $v$)
3. cannot be zero
4. none of the above

Q. A heavy uniform rod is hanging vertically from a fixed support. It is stretched by its own weight. The diameter of the rod is :

1. Smallest at the top and gradually increases down the rod
2. Largest at the top and gradually decreases down the rod
3. Uniform everywhere
4. maximum int he middle

Q. Weight of the block will be.

1. constant
2. increasing
3. decreasing
4. none of these

Q. A body weighs $9g$ when placed in one pan of a faulty balance. It weighs $16g$ when placed in the other pan of the same balance. If the beam remains horizontal when the pans are empty, what is the true weight of the body?

1. $5g$
2. $12g$
3. $25g$
4. $7g$

Q. Two unequal masses $m_1$ and $m_2$ are connected by a string going over a clamped light smooth pulley as shown in figure $m_1=3kg$ and $m_2=6kg$ . The system is released from rest (a) Find the distance traveled by the first block the first two seconds. $g=10m/s^2$

Q. An object is kept on a smooth inclined plane of inclination ${\sin }^{-1}\left(\frac{1}{L}\right)$ can be kept stationary relative to the incline by giving a horizontal acceleration of ______

1. $\frac{g}{L^2+1}$ to the inclined plane
2. $\frac{g}{\sqrt{L^2-1}}$ to the inclined plane
3. $\frac{g}{L^2-1}$ to the inclined plane
4. $\frac{g}{\sqrt{L^2+1}}$ to the inclined plane

Q. A block rests on a rough plane whose inclination angle $\theta$ with horizontal is increased (gradually), then contact force(C) between block & plane varies with $\theta$ (consider interval before block slips)

1. 
2. 
3. 
4. 

Q. A block rests on a rough plane whose inclination angle $\theta$ with horizontal is increased (gradually), then contact force(C) between block & plane varies with $\theta$ (consider interval before block slips)

1. 
2. 
3. 
4. 

Q. A body weighs 8 gm, when placed in one pan and 18gm, when placed in the other pan of a false balance. The beam is horizontal (when both the pans are empty), the true weight of the body is

1. 13 gm
2. 12 gm
3. 15.5 gm
4. 15 gm

Q. Three weights W, 2W and 2W are connected to identical springs suspended form rigid lkhorizontal rod. The assembly of the rod and the weights fall freely. The positions of the weights from the rod are such that

1. 3W will be farthest
2. W will be farthest
3. All will be at the same distance
4. 2 W will be farthest