JEE Main Physics - Description of Motion in Two and Three Dimension
Exam Duration: 60 Mins Total Questions : 30
The angular frequency of the minute hand of a clock is (in rad s-1)
- (a)
\(\frac{1}{60}\)
- (b)
\(\frac{\pi}{180}\)
- (c)
\(\frac{\pi}{60}\)
- (d)
\(\frac{\pi}{1800}\)
In the wheels of a rail train,flanges are essential to provide the carriages the necessary
- (a)
uniform velocity
- (b)
uniform acceleration
- (c)
centripetal force
- (d)
centrifugal force
A bullet is fired with a speed of 1000 ms-1 in order to hit a target 100 m away.If g = 10 ms-2 ,the gun should be aimed at
- (a)
directly towards the target
- (b)
5 cm above the target
- (c)
10 cm above target
- (d)
15 cm above the target
A ball of mass m is thrown vertically up and another ball of mass 2m is thrown at an angle \(\theta\). If their times of ascent are equal, then the height attained by them are in the ratio of
- (a)
1 : 1
- (b)
2 : 1
- (c)
1 : cos \(\theta\)
- (d)
1 : sec \(\theta\)
Find the angle between force \(F=(3\hat i+4\hat j-5\hat k)\) and displacement \(d=(5\hat i + 4\hat j + 3\hat k)\) unit.
- (a)
\(cos^{-1}(0.32)\)
- (b)
\(cos^{-2}(0.32)\)
- (c)
\(cos^{-1}(0.42)\)
- (d)
\(cos^{-2}(0.42)\)
If R is the maximum horizontal range of a particle, then the greatest height attained by it is:
- (a)
R
- (b)
2R
- (c)
R/2
- (d)
R/4
A ball is thrown from a point with a speed vo at an angle of projection θ.From the same point and at the same instant a person starts running with a constant speed vo /2 to catch the ball. Will the person be able to catch the ball? If yes, what should be the angle of projection?
- (a)
Yes, 60°
- (b)
Yes, 30°
- (c)
No
- (d)
Yes, 45°
A body is projected at an angle of 30° with the horizontal and with a speed of 30 ms-1. What is the angle with the horizontal after 1.5 seconds? (Take g = 10ms-2)
- (a)
0°
- (b)
30°
- (c)
60°
- (d)
90°
The range of a rifle bullet on level ground is 6000 m. The range at an incline of 30° is
- (a)
4000 m
- (b)
2000 m
- (c)
6000 m
- (d)
1000 m
The maximum height attained by a projectile is increased by 5%. Keeping the angle of projection constant, what is the percentage increase in horizontal range?
- (a)
5%
- (b)
10%
- (c)
15%
- (d)
20%
Two paper screens A and B are separated by 150 m. A bullet pierces A and then B. The hole in B is 15 em below the hole in A. If the bullet is travelling horizontally at the time of hitting A, then the velocity of the bullet at A is:
- (a)
100√3ms-1
- (b)
200√3ms-1
- (c)
300√3ms-1
- (d)
500√3ms-1
Which of the following is the largest, when the height attained by the projectile is the largest?
- (a)
Range
- (b)
Time of flight
- (c)
Time of flight
- (d)
None of the above
A projectile is thrown in the upward direction making an angle of 60° with the horizontal direction with a velocity of 147 ms-1 , then the time after which its inclination with the horizontal is 45°, is:
- (a)
15s
- (b)
10.98s
- (c)
5.49s
- (d)
2.745s
A particle is projected with a velocity u making an angle e with the horizontal. At any instant, its velocity V is at right angles to its initial velocity u ; then V is:
- (a)
u cos θ
- (b)
u tan θ
- (c)
u cot θ
- (d)
u sec θ
A person sitting in the rear end of the compartment throws a ball towards the front end. The ball follows a parabolic path. The train is moving with uniform velocity of 20 m s -1 . A person standing outside on the ground also observes the ball. How will the maximum heights (hm ) attained and the ranges (R) seen by the thrower and the outside observer compare each other?
- (a)
Same hm different R
- (b)
Same hm and R
- (c)
Different hm same R
- (d)
Different hm and R
A vehicle of mass 1500 kg is moving along a curved path of length 314 m with a speed of 20 ms -1. If it takes a turn of 90°, the centripetal force needed by the vehicle is:
- (a)
1000 N
- (b)
2000 N
- (c)
3000 N
- (d)
4000 N
A car takes a circular turn with a uniform speed V. If the reaction at inner and outer wheels be denoted by R1 and R2, then:
- (a)
R1= R2
- (b)
R1 < R2
- (c)
R1 > R2
- (d)
R1 ≷ R2
A hollow vertical cylinder of radius R and height h has smooth internal surface. A small particle is placed in contact with the inner side of the upper rim at a point P.It is given a horizontal speed Vo tangential to rim. It leaves the lower rim at point Q, vertically below P. The number of revolutions made by the particle will be:
- (a)
\(h\over 2\pi R\)
- (b)
\(v_0\over \sqrt{2gh}\)
- (c)
\(2\pi R\over h\)
- (d)
\({v_0\over 2\pi R}\left(\sqrt{h\over g}\right)\)
A spirit level is placed at the edge of a turn-table along its radius. The bubble will lie:
- (a)
at the centre
- (b)
at the outer edge
- (c)
at the inner edge
- (d)
will oscillate about the centre
A particle is projected from a horizontal plane with a velocity of 8√2 m/s at an angle. At the highest point, its velocity is found to be 8 m/s. Its range will be:
- (a)
6.4 m
- (b)
3.2 m
- (c)
12.8 m
- (d)
4.6 m
For angles of projection of a projectile at angles (45° - θ) and (45°+θ), the horizontal range described by the projectile are in the ratio of:
- (a)
2 : 1
- (b)
1 : 1
- (c)
2 : 3
- (d)
1 : 2
A cart is moving horizontally along a straight line with constant speed 30 m/s. A projectile is to be fired from the moving cart in such a way that it will return to the cart after the cart has moved 80 m. At what speed (relative to the cart) must the projectile be fired?
- (a)
10 m/s
- (b)
10√8 m/s
- (c)
40/3 m/s
- (d)
None of these
A fielder in a cricket match throws ball from the boundary line to the wicket keeper. The ball describes a parabolic path. Which of the following quantities remain constant during the motion in air?
- (a)
Kinetic energy
- (b)
Vertical component of velocity
- (c)
Horizontal component of velocity
- (d)
Speed
A body is projected with a velocity \(\vec v=(3\vec i+4\vec j)m/s\).The maximum height attained by the body is:
- (a)
0.8m
- (b)
8m
- (c)
80m
- (d)
800m
The coordinates of a particle moving in x-y plane at any instant of time t are x=4t2; y=3t2 . The speed of the particle at that instant is:
- (a)
10 t
- (b)
5 t
- (c)
3 t
- (d)
2 t
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