The Simple Pulley

Q.

The mechanical advantage of a machine is $4$ and its efficiency is $60\%$. It is used to lift a load of $300\mathrm{kgf}$ to a height of $15\mathrm{m}$. Calculate
(i) The effort required.
(ii) The work done on the machine.
(Take, $\mathrm{g}=10\mathrm{m}/{\mathrm{s}}^2$)

Q. Define velocity

Q.

What is the efficiency of a machine, given mechanical advantage is $2$ and velcoity ratio is $4$?

Q. A motor boat going down stream, overtakes a floating object in water. One hour later, the motor boat turnedback. If speed of motor boat in still water is constant and flow velocity is also assumed constant, motorboat will again pass the floating object ater time t given by(1) Greater than 2 hours (2) Equal to 2 hours(3) Less than 2 hours (4) Less than 1 hour

Q. Choose the correct statements regarding momentum.
Statement 1: Momentum has both direction and magnitude.
Statement 2: SI unit of momentum is ${kgms}^{-1}$.
Statement 3: A balanced force can create a change in velocity.
Statement 4: An unbalanced force can create a change in velocity.
Statement 5: A balanced force can create a change in momentum.
Statement 6: A unbalanced force can create a change in momentum.

1. All statements, except 5
2. All statements except 5 and 3
3. All statements except 2
4. All statements except 1

Q. An effort of $240\text{N}$ overcome a useful load $1000\text{N}$ when applied to a block and system of pulleys; such that the weight of movable block and friction is $220\text{N}$. What is the efficiency of the system?

1. $81.2\%$
2. $82.5\%$
3. $83.4\%$
4. $84\%$

Q.

The momentum of an object depends on its:

1. mass alone
2. velocity alone
3. distance
4. mass and velocity

Q. motion