Combined Quiz 1_11th_saarthi

ASSERTION (A): A body can have acceleration even if its velocity is zero at a given instant of time. REASON (R): A body is momentarily at rest when it reverses its direction.

• Both A and R are true and R is the correct explanation of A
• Both A and R are true and R is not the correct explanation of A
• A is true but R is false
• A is false but R is true

The position of a particle is given by x = (t-2)^2 where x is in metre and t is in seconds. The distance covered by the particle in first 4 seconds is

• 4m
• 8m
• 12m
• 16m

A boat can be rowed at 5 m/s in still water. It is used to cross a 200m wide river from south bank to the north bank. The river current has uniform velocity of 3 m/s due east. In which direction must it be steered to cross the river perpendicular to current?

• 37◦
• 30◦
• 60◦
• 90◦

A body is projected with a speed u m/s at an angle β with the horizontal. The kinetic energy at the highest point is 3/4th of the initial kinetic energy. The value of β is

• 30◦
• 45◦
• 60◦
• 120◦

What is the angle between vector A = i+j and B = i-j where i,j are unit vectors in x and y direction respectively

• 45◦
• 90◦
• -45◦
• 180◦

An aeroplane is flying horizontally with a velocity of 600 km/h and at a height of 1960 m. When it is vertically above a point A on the ground, a bomb is released from it. The bomb strikes the ground at point B. The distance AB is

• 1200 m
• 0.33 km
• 33.3 km
• 3.33 km

ASSERTION (A) : In the presence of air friction, if the ball is thrown vertically upwards, the time of ascent is less than the time of descent. REASON (R) : Force due to air friction always acts opposite to the motion of the body.

• Both A and R are true and R is the correct explanation of A
• Both A and R are true and R is not the correct explanation of A
• A is true but R is false
• A is false but R is true

A stone starts to fall under gravity. The distances covered by it in first, second and third second are in ratio -

• 01:03:05
• 01:02:03
• 01:04:09
• 01:05:09

A bus is moving with a speed of 10 m/s on a straight road. A person on a scooter wishes to overtake the bus in 50 seconds. If the bus is at a distance of 1 km from the person, with what speed should the person chase the bus?

• 50 m/s
• 60 m/s
• 80 m/s
• 30 m/s

One car moving on a straight road covers one third of the distance with a speed of 20 m/s, other one third with a speed of 40 m/s and next one third with speed of 60 m/s, then the average speed of the car is :

• 32.7 m/s
• 40 m/s
• 31 m/s
• 33 m/s