25-MinuteTest: Acceleration - JEE MCQ

Acceleration = – 4m/s²; Initial speed, u = 60 m s^-1

Time taken = 5s

Acceleration = change in velocity per unit time

a=v-u/t

v= u + at

v = 60 – 4 x 5 = 40 m/s

Both velocity and acceleration are in the downward direction. Thus, they will be considered negative as they are vectors and the upward direction is positive.

u = 20 m/s, a = -4 m/s², t = 2 s.
v = ?
∵ v = u + at
⇒ v = 20 + (-4) (2)
⇒ v = 20 - 8 = 12 m/s

• When the ball moves upward, the force of gravitation is acting in the opposite direction of the ball that is why in that case acceleration is negative or in other words deceleration takes place.
• But when the ball is moving downwards the force of gravitation is in the same direction of the motion of the ball thus acceleration takes place in this case.

• Distance is a scalar quantity that refers to "how much ground an object has covered" during its motion. 
• Acceleration is a vector quantity that is defined as the rate at which an object changes its velocity.
• Velocity is a vector quantity that refers to the speed of an object in a particular direction.

M.K.S. unit of acceleration = 1 m/s²
C.G.S. unit of acceleration = 1 cm/s²

C.G.S unit of acceleration/ M,K.S unit of acceleration = 1 cm/s² / 1 m/s²
= 1 cm / 100 cm = 1/100 =1:100

Calculating acceleration involves dividing velocity by time or we can say,  dividing the meter per second by the second. i.e. [ m/s² = (m/s) /s ]

If a moving body comes to rest, then its acceleration is negative, as it's velocity becomes zero.

If the average velocity of a body equals the mean of its initial and final velocities, it indicates that the body moves with a consistent acceleration throughout its motion. This is because:

• The average velocity is calculated as: (Initial Velocity + Final Velocity) / 2.
• When the average velocity matches this formula, it implies the body does not speed up or slow down.
• Therefore, the acceleration is uniform, meaning it remains constant during the motion.

Acceleration is a vector quantity that is defined as the rate at which an object changes its velocity. An object is accelerating if it is changing its velocity.