The machine as shown has \(2\) rods of length \(1~\text{m}\) connected by a pivot at the top. The end of one rod is connected to the floor by a stationary pivot and the end of the other rod has a roller that rolls along the floor in a slot. As the roller goes back and forth, a \(2~\text{kg}\) weight moves up and down. If the roller is moving towards the right at a constant speed, the weight moves up with a:
1. speed which is \(\frac{3}{4}\text{th}\) of that of the roller when the weight is \(0.4~\text{m}\) above the ground
2. constant speed
3. decreasing speed
4. increasing speed 
Subtopic:  Speed & Velocity |
Level 4: Below 35%
Please attempt this question first.
Hints
Please attempt this question first.

Ship \(A\) is sailing towards north-east with velocity \(\vec{v}=30 \hat{i}+50 \hat{j}+50 \hat{i}~ \text{km/hr}\) where \(\hat{i}\) and \(\hat{j}\) north. Ship \(B\) is at a distance of \(80~\text{km}\) east and \(150~\text{km}\) north of Ship \(A\) and is sailing towards west at \(10~\text{km/hr}\). \(A\) will be at minimum distance from \(B\) in:
1. \(4.2~\text{hrs}\)
2. \(2.2~\text{hrs}\)
3. \(2.6~\text{hrs}\)
4. \(3.2~\text{hrs}\)

Subtopic:  Relative Motion |
Level 3: 35%-60%
JEE
Please attempt this question first.
Hints
Please attempt this question first.

The stream of a river is flowing with a speed of \(2~\text{km/h}\). A swimmer can swim at a speed of \(4~\text{km/h}\). What should be the direction of the swimmer with respect to the flow of the river to cross the river straight?
1. \( 60^{\circ} \)
2. \( 90^{\circ} \)
3. \( 150^{\circ} \)
4. \( 120^{\circ}\)

Subtopic:  Relative Motion |
 74%
Level 2: 60%+
JEE
Please attempt this question first.
Hints
Please attempt this question first.

advertisementadvertisement

The position vector of a particle changes with time according to the relation,
\(\vec{r}(t)=(15 t^2) \hat{i}+\left(4-20 t^2\right) \hat{j},\) where \(\vec{r}(t)\) is in metres and \(t\) is in seconds.
What is the magnitude of the acceleration at \(t=1\) second?  
1. \(100\) m/s2 2. \(40\) m/s2
3. \(50\) m/s2 4. \(25\) m/s2
Subtopic:  Acceleration |
 84%
Level 1: 80%+
JEE
Please attempt this question first.
Hints
Please attempt this question first.

A particle is projected with a speed of \(2~\text{m/s}\) from the base of a plane inclined at \(30^\circ\) to the horizontal. The direction of projection makes an angle of \(15^\circ\) above the inclined plane as shown in the figure. If \(g=10~\text{m/s}^2,\) what is the distance along the plane from the point of projection to the point where the particle strikes the plane?

             
1. \(14~\text{cm}\)
2. \(28~\text{cm}\)
3. \(20~\text{cm}\)
4. \(36~\text{cm}\)

Subtopic:  Projectile Motion |
 55%
Level 3: 35%-60%
Please attempt this question first.
Hints
Please attempt this question first.

A shell is fired from a fixed artillery gun with an initial speed \(u\) such that it hits the target on the ground at a distance \(R\) from it. If \(t_1\) and \(t_2\) are the values of the time taken by it to hit the target in two possible ways, the product \(t_1t_2\) is:
1. \(\frac{2R}{g}\)
2. \(\frac{R}{2g}\)
3. \(\frac{R}{g}\)
4. \(\frac{R}{4g}\)

Subtopic:  Projectile Motion |
 79%
Level 2: 60%+
JEE
Please attempt this question first.
Hints
Please attempt this question first.

advertisementadvertisement

The trajectory of a projectile near the surface of the earth is given as \(y=2x-9x^2\). If it were launched at an angle \(\theta_0\) with speed \(v_0\) then:\(\left(g= 10~\text{ms}^{-2}\right)\)

1. \(\theta_0=\cos^{-1}\left(\frac{1}{\sqrt{5}}\right) \text{ and }v_0=\frac{5}{3}~\text{ms}^{-1}\)
2. \(\theta_0=\cos^{-1}\left(\frac{2}{\sqrt{5}}\right) \text{ and }v_0=\frac{3}{5}~\text{ms}^{-1}\)
3. \(\theta_0=\sin^{-1}\left(\frac{2}{\sqrt{5}}\right) \text{ and }v_0=\frac{3}{5}~\text{ms}^{-1}\)
4. \(\theta_0=\sin^{-1}\left(\frac{1}{\sqrt{5}}\right) \text{ and }v_0=\frac{5}{3}~\text{ms}^{-1}\)
Subtopic:  Projectile Motion |
 73%
Level 2: 60%+
JEE
Please attempt this question first.
Hints
Please attempt this question first.

Two particles are projected from the same point with the same speed \(u,\) but at different angles. They both cover the same horizontal range \(R,\) but reach different maximum heights, \(h_1\)​ and \(h_2.\) Which of the following relations is correct?

1. \(R^2=h_1h_2\) 2. \(R^2=16h_1h_2\)
3. \(R^2=4h_1h_2\) 4. \(R^2=2h_1h_2\)
Subtopic:  Projectile Motion |
 69%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.

A particle is moving with a velocity \(\vec v=K(y \hat{i}+x\hat{j}),\) where \(K\) is a constant. The general equation for its path is: 
1. \(y=x^2+\text{constant}\)
2. \(y^2=x+\text{constant}\)
3. \(y^2=x^2+\text{constant}\)
4. \(xy=\text{constant}\)
Subtopic:  Position & Displacement |
 70%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.

advertisementadvertisement

A particle starts from the origin at time \(t=0 \) with an initial velocity of \(5\hat{j}~\text{ms}^{-1}. \) It moves in the \(XY \text-\)plane under a constant acceleration of \(\left(10\hat{i}+4\hat{j}\right)~\text{ms}^{-2} .\) At some later time \(t,\) the coordinates of the particle are \((20~\text{m}, y_0~\text{m}). \) The values of \(t \) and \(y_0 \)​ are, respectively:
1. \(4~\text{s}\) and \(52~\text{m}\)
2. \(5~\text{s}\) and \(25~\text{m}\)
3. \(2~\text{s}\) and \(18~\text{m}\)
4. \(2~\text{s}\) and \(24~\text{m}\)

Subtopic:  Position & Displacement |
 81%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.