Directions : Each question contains STATEMENT-1 and STATEMENT-2. Choose the correct answer(ONLY ONE option is correct ) from the following

(a)Statement -1 is false, Statement-2 is true

(b)Statement -1 is true, Statement-2 is true; Statement -2 is a correct explanation for Statement-1

(c)Statement -1 is true, Statement-2 is true; Statement-2 is not a correct explanation for Statement-1

(d)Statement -1 is true, Statement-2 is false

Statement-1: Centripetal and centrifugal forces cancel each other.

Statement-2 : This is because they are always equal and opposite.

View Ans & Explanation
(a)Statement -1 is false, Statement-2 is true

A wheel rotates with constant acceleration of 2.0 rod/s², if the wheel starts from rest the number of revolutions it makes in the first ten seconds will be approximately

Solution

A projectile can have the same range for two angles of projection. If h₁ and h₂ are maximum heights when the range in the two cases is R, then the relation between R, h₁ and h₂ is

R=\(4\sqrt{h_{1}h_{2}}\)
R=\(2\sqrt{h_{1}h_{2}}\)
R=\(\sqrt{h_{1}h_{2}}\)
None of these

Solution

A body is projected horizontally from a point above the ground and motion of the body is described by the equation x = 2t, y = 5t² where x, and y are horizontal and vertical coordinates in metre after time t. The initial velocity of the body will be

√29 m/s horizontal
5 m/s horizontal
2 m/s vertical
2 m/s horizontal

Solution

The horizontal velocity of the projectile remains constant throughout the journey.Since the body is projected horizontally, the initial velocity will be same as the horizontal velocity at any point.

Since, x = 2t,^dx⁄_t=2

∴ Horizontal velocity = 2 m/s

∴ Initial velocity = 2 m/s

A ball is projected at such an angle that the horizontal range is three times the maximum height. The angle of projection of the ball is

\(sin^{-1}\left ( \frac{3}{4} \right )\)
\(sin^{-1}\left ( \frac{4}{3} \right )\)
\(cos^{-1}\left ( \frac{4}{3} \right )\)
\(tan^{-1}\left ( \frac{4}{3} \right )\)

Solution

Given\(\frac{u^{2}sin2\theta }{g}=3\frac{u^{2}sin^{2}\theta }{2g}\)

⇒ θ=\(tan^{-1}\left ( \frac{4}{3} \right )\)

A bomb is dropped on an enemy post by an aeroplane flying horizontally with a velocity of 60 km h^-1 and at a height of 490 m. At the time of dropping the bomb, how far the aeroplane should be from the enemy post so that the bomb may directly hit the target ?

\(\frac{400}{3}m\)
\(\frac{500}{3}m\)
\(\frac{1700}{3}m\)
498 m.

Solution

A bomb is released from a horizontal flying aeroplane. The trajectory of bomb is

a parabola
a straight line
a circle
a hyperbola

Solution

a parabola

A particle moves in acircle of radius 25 cm at two revolutions per second. The acceleration of the particle in meter per second² is

π²
8 π²
4 π²
2 π²

Solution

Two particles of equal masses are revolving in circular paths of radii r₁ and r₂ respectively with the same period. The ratio of their centripetal force is

r₁/r₂
r₁/r₂
(r₁/r₂)²
(r₂/r₁)²

Solution

A ball is thrown from the ground with a velocity of 20√3 m/s making an angle of 60º with the horizontal. The ball will be at a height of 40 m from the ground after a time t equal to(g = 10 ms²)

√2 sec
√3 sec
2 sec
3 sec

Solution

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