Kinematics

The magnitude of average velocity is equal to average speed when the particle moving with ____

• variable speed

• constant velocity

• variable velocity

• constant acceleration

A swimmer's speed in the direction of flow of river is 16 km h ^-1 . Against the flow of river, the swimmer's speed is 8 km h ^-1 . The swimmer's speed in still water and the velocity of flow of the river respectively are

• 12 km h ^{-1 ,} 4 km h ^-1

• 4 km h ^-1 ,12 km h ^-1

• 24 km h ^-1 ,16 km h ^-1

• 16 km h ^-1 ,24 km h ^-1

A particle is thrown vertically upward. Its velocity at half of the height is 10 m /s then the maximum height attained by it is ( g = 10m/s²)

• 8m

• 20m

• 10m

• 16m

If the velocity is v = 2i + t²j - 9 k , then the magnitude of acceleration at t = 0.5 s is ___

• 1 m s ^-2

• 2 m s ^-2

• zero

• -1 m s ^-2

Which one of the following Cartesian

coordinate systems is not followed in

physics?

• 
• 
• 
• 

Identify the unit vector in the following.

• 
• 
• 
• 

Which one of the following physical

quantities cannot be represented by a

scalar?

• Mass

• length

• momentum

• magnitude of acceleration

Two objects of masses m1 and m2 fall

from the heights h1 and h2 respectively.

The ratio of the magnitude of their

momenta when they hit the ground is

• 
• 
• 
• 

If a particle has negative velocity and

negative acceleration, its speed

• increases

• decreases

• remains same

• zero

If an object is dropped from the top of

a building and it reaches the ground at t

= 4 s , then the height of the building is

(ignoring air resistance) (g = 9.8 ms–2)

• 77.3 m

• 78.4 m

• 80.5 m

• 79.2 m