Motion in a Plane · Question 25

A projectile is fired at an angle of 45 with the horizontal. Elevation angle of the projectile at its highest point as seen from the point of projection, is

1. 45
2. 60
3. -1 ( 12 )
4. -1 ( 32 )

A particle moves in a circle of radius 5 cm with constant speed and time period 0.2 s. The acceleration of the particle is

1. 15 m/s2
2. 25 m/s2
3. 36 m/s2
4. 5 m/s2

A missile is fired for maximum range with an initial velocity of 20 m/s. If g = 10 m/s2, the range of the missile is

1. 40 m
2. 50 m
3. 60 m
4. 20 m

A body is moving with velocity 30 m/s towards east. After 10 seconds its velocity becomes 40 m/s towards north. The average acceleration of the body is

1. 1 m/s2
2. 7 m/s2
3. 7 m/s2
4. 5 m/s2

The speed of a projectile at its maximum height is half of its initial speed. The angle of projection is

1. 60
2. 15
3. 30
4. 45

A particle moves in x-y plane according to rule x = a t and y = a t. The particle follows

1. an elliptical path
2. a circular path
3. a parabolic path
4. a straight line path inclined equally to x and y-axes

A particle has initial velocity (3 i + 4 j) and has acceleration (0.4 i + 0.3 j). Its speed after 10 s is

1. 7 units
2. 7 2 units
3. 8.5 units
4. 10 units

Six vectors, a through f have the magnitudes and directions indicated in the figure. Which of the following statements is true? [figure]

1. b + c = f
2. d + c = f
3. d + e = f
4. b + e = f

A particle of mass m is projected with velocity v making an angle of 45 with the horizontal. When the particle lands on the level ground the magnitude of the change in its momentum will be :

1. mv 2
2. zero
3. 2mv
4. mv/ 2

A and B are two vectors and θ is the angle between them. If | A B| = 3 ( A B), the value of θ is

1. 45
2. 30
3. 90
4. 60