Acceleration — JEE Main Physics MCQs with Solutions
Free JEE Main Physics Acceleration MCQs with step-by-step solutions (36 questions). Part of Motion in 1 Dimension. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Acceleration · medium · theory
Acceleration is defined as
A. The rate of change of position
B. The rate of change of velocity ✓ Correct
C. Velocity × time
D. The rate of change of distance
Solution: $\vec a = \frac{d\vec v}{dt}$.
Q2 — Acceleration · medium · theory
The SI unit of acceleration is
A. m/s
B. N
C. m²/s
D. m/s² ✓ Correct
Solution: Change in velocity (m/s) per second gives m/s².
Q3 — Acceleration · medium · numerical
A car speeds up from $10$ m/s to $30$ m/s in $4$ s. Its acceleration is
A. $4$ m/s²
B. $5$ m/s² ✓ Correct
C. $7.5$ m/s²
D. $10$ m/s²
Solution: $a = \frac{30-10}{4} = 5$ m/s².
Q4 — Acceleration · medium · numerical
A body starts at $5$ m/s with uniform acceleration $2$ m/s². Its velocity after $3$ s is ($v = u + at$)
A. $6$ m/s
B. $11$ m/s ✓ Correct
C. $10$ m/s
D. $16$ m/s
Solution: $v = 5 + 2\times3 = 11$ m/s.
Q5 — Acceleration · medium · theory
A body starts from rest with uniform acceleration $4$ m/s². The distance covered in $3$ s is ($s = ut + \frac{1}{2}at^2$)
A. $12$ m
B. $6$ m
C. $18$ m ✓ Correct
D. $36$ m
Solution: $s = 0 + \frac{1}{2}\times4\times9 = 18$ m.
Q6 — Acceleration · medium · numerical
A body starting from rest attains a velocity of $20$ m/s over a distance of $100$ m. Its uniform acceleration is ($v^2 = u^2 + 2as$)
A. $5$ m/s²
B. $4$ m/s²
C. $0.2$ m/s²
D. $2$ m/s² ✓ Correct
Solution: $400 = 0 + 2a(100) \Rightarrow a = 2$ m/s².
Q7 — Acceleration · medium · theory
With the same braking force, the stopping distance of a car is proportional to
A. Its speed
B. The cube of its speed
C. The square of its speed ✓ Correct
D. The square root of its speed
Solution: From $v^2 = 2as$: $s = \frac{v^2}{2a}$ — double the speed, four times the distance.
Q8 — Acceleration · medium · theory
A car doubles its speed. With the same braking deceleration, its stopping distance becomes
A. $4$ times ✓ Correct
B. The same
C. $2$ times
D. $8$ times
Solution: $s \propto v^2$: doubling $v$ quadruples the stopping distance.
Q9 — Acceleration · medium · numerical
A car slows from $20$ m/s to rest in $5$ s. Its acceleration is
A. $-4$ m/s² ✓ Correct
B. $-5$ m/s²
C. $-20$ m/s²
D. $4$ m/s²
Solution: $a = \frac{0-20}{5} = -4$ m/s² (retardation of 4 m/s²).
Q10 — Acceleration · medium · theory
A body starts from rest with acceleration $2$ m/s². The distance covered in the $5$th second is $\left(s_n = u + \frac{a}{2}(2n-1)\right)$
A. $25$ m
B. $10$ m
C. $9$ m ✓ Correct
D. $5$ m
Solution: $s_5 = 0 + \frac{2}{2}(2\times5 - 1) = 9$ m.
Q11 — Acceleration · easy · theory
The slope of a velocity–time graph gives
A. Distance
B. Acceleration ✓ Correct
C. Speed
D. Displacement
Solution: $a = \frac{dv}{dt}$ — the slope of $v$ against $t$.
Q12 — Acceleration · medium · theory
A body has uniform acceleration if its velocity changes by
A. Equal amounts in equal distances
B. Equal amounts in equal intervals of time ✓ Correct
C. Zero
D. Unequal amounts uniformly
Solution: Constant $a$ means the same $\Delta v$ every second.
Q13 — Acceleration · easy · theory
A body is said to be decelerating (slowing down) when
A. Its velocity is negative
B. Its acceleration is negative
C. Its acceleration is zero
D. Its acceleration is opposite to its velocity ✓ Correct
Solution: Slowing down means $\vec a$ opposes $\vec v$ — the SIGN alone of $a$ doesn’t decide it.
Q14 — Acceleration · medium · numerical
The position of a particle is $x = t^3$ (metres, seconds). Its acceleration at $t = 2$ s is
A. $6$ m/s²
B. $8$ m/s²
C. $12$ m/s² ✓ Correct
D. $4$ m/s²
Solution: $v = 3t^2$, $a = 6t$; at $t=2$: $a = 12$ m/s².
Q15 — Acceleration · medium · numerical
The velocity of a particle is $v = 3t^2$ (m/s, seconds). Its acceleration at $t = 1$ s is
A. $9$ m/s²
B. $3$ m/s²
C. $1$ m/s²
D. $6$ m/s² ✓ Correct
Solution: $a = \frac{dv}{dt} = 6t$; at $t=1$: $6$ m/s².
Q16 — Acceleration · medium · theory
A ball is thrown straight up. During its ENTIRE flight (ignoring air), its acceleration is
A. Changing continuously
B. $g$ upward while rising
C. $g$ downward throughout ✓ Correct
D. Zero at the top
Solution: Gravity acts the same at all times — even at the top where velocity is momentarily zero.
Q17 — Acceleration · medium · theory
If the acceleration of a body is zero, its motion is
A. Uniform velocity (or rest) ✓ Correct
B. Circular
C. Uniformly accelerated
D. Impossible
Solution: No acceleration means velocity never changes.
Q18 — Acceleration · easy · theory
A body moving at $10$ m/s decelerates uniformly at $2$ m/s². The time it takes to stop is
A. $2$ s
B. $5$ s ✓ Correct
C. $20$ s
D. $10$ s
Solution: $0 = 10 - 2t \Rightarrow t = 5$ s.
Q19 — Acceleration · medium · theory
A body moving at $10$ m/s decelerates uniformly at $2$ m/s². The distance it covers before stopping is
A. $50$ m
B. $5$ m
C. $10$ m
D. $25$ m ✓ Correct
Solution: $0 = 100 - 2(2)s \Rightarrow s = 25$ m.
Q20 — Acceleration · medium · numerical
A train speeds up from $36$ km/h to $72$ km/h in $10$ s. Its acceleration is
A. $2$ m/s²
B. $1$ m/s² ✓ Correct
C. $0.5$ m/s²
D. $3.6$ m/s²
Solution: Convert: $10$ m/s $\to 20$ m/s. $a = \frac{20-10}{10} = 1$ m/s².
Q21 — Acceleration · medium · theory
Can the speed of a body increase while its acceleration is decreasing?
A. Yes — as long as acceleration stays in the direction of motion ✓ Correct
B. No, never
C. Only if velocity is negative
D. Only in free fall
Solution: A shrinking but still-forward acceleration keeps adding speed, just more slowly.
Q22 — Acceleration · medium · theory
A particle has positive velocity and constant negative acceleration. It is currently
A. Moving with uniform velocity
B. At rest
C. Slowing down ✓ Correct
D. Speeding up
Solution: Acceleration opposite to velocity always means slowing down.
Q23 — Acceleration · medium · numerical
A body starts from rest with uniform acceleration. The ratio of distances covered in the 1st, 2nd and 3rd seconds is
A. $1:4:9$
B. $1:3:5$ ✓ Correct
C. $1:1:1$
D. $1:2:3$
Solution: Distances in successive seconds follow the odd numbers (Galileo’s rule): $1:3:5:7\ldots$
Q24 — Acceleration · medium · theory
The area under an acceleration–time graph gives
A. Distance
B. Average speed
C. Change in velocity ✓ Correct
D. Displacement
Solution: $\int a\,dt = \Delta v$.
Q25 — Acceleration · medium · numerical
A body starts from rest with uniform acceleration and covers $16$ m in $2$ s. Its acceleration is
A. $16$ m/s²
B. $4$ m/s²
C. $8$ m/s² ✓ Correct
D. $2$ m/s²
Solution: $16 = \frac{1}{2}a(4) \Rightarrow a = 8$ m/s².
Q26 — Acceleration · medium · numerical
A body starts from rest with uniform acceleration. The ratio of its velocities at times $t$ and $2t$ is
A. $1:4$
B. $1:2$ ✓ Correct
C. $2:1$
D. $1:\sqrt{2}$
Solution: $v = at \propto t$: at double the time, double the velocity.
Q27 — Acceleration · medium · theory
A body moving with constant (non-zero) acceleration can
A. Reverse its direction of motion ✓ Correct
B. Only move in a straight line forever
C. Never change direction
D. Not have zero velocity
Solution: Example: a ball thrown upward — constant $g$ downward, yet the motion reverses at the top.
Q28 — Acceleration · medium · theory
For uniformly accelerated motion, the average velocity over an interval equals
A. $\frac{u+v}{2}$ ✓ Correct
B. $\sqrt{uv}$
C. $\frac{2uv}{u+v}$
D. $v - u$
Solution: Velocity changes linearly with time, so the average is the mean of the initial and final values.
Q29 — Acceleration · medium · theory
A particle starts at $20$ m/s with acceleration $-10$ m/s². Its velocity at $t = 3$ s is
A. $10$ m/s
B. Zero
C. $-30$ m/s
D. $-10$ m/s (10 m/s in the reverse direction) ✓ Correct
Solution: $v = 20 - 10\times3 = -10$ m/s — it stopped at $t=2$ s and reversed.
Q30 — Acceleration · medium · theory
The dimensional formula of acceleration is
A. $[L^2T^{-2}]$
B. $[LT^{-2}]$ ✓ Correct
C. $[MLT^{-2}]$
D. $[LT^{-1}]$
Solution: Velocity per time: $[LT^{-1}]/[T] = [LT^{-2}]$.