Motion Under Gravity — JEE Main Physics MCQs with Solutions
Free JEE Main Physics Motion Under Gravity MCQs with step-by-step solutions (37 questions). Part of Motion in 1 Dimension. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Motion Under Gravity · easy · theory
A body is dropped from rest. The distance it falls in $2$ s is (take $g = 10$ m/s²)
A. $20$ m ✓ Correct
B. $10$ m
C. $40$ m
D. $5$ m
Solution: $h = \frac{1}{2}gt^2 = \frac{1}{2}\times10\times4 = 20$ m.
Q2 — Motion Under Gravity · easy · numerical
A body falls freely from rest. Its velocity after $3$ s is ($g = 10$ m/s²)
A. $30$ m/s ✓ Correct
B. $90$ m/s
C. $10$ m/s
D. $45$ m/s
Solution: $v = gt = 10\times3 = 30$ m/s.
Q3 — Motion Under Gravity · medium · numerical
A body dropped from rest has fallen $20$ m. Its speed at that point is ($g = 10$ m/s²)
A. $40$ m/s
B. $10$ m/s
C. $200$ m/s
D. $20$ m/s ✓ Correct
Solution: $v = \sqrt{2gh} = \sqrt{2\times10\times20} = 20$ m/s.
Q4 — Motion Under Gravity · easy · theory
A ball is thrown up at $20$ m/s. The maximum height reached is ($g = 10$ m/s²)
A. $80$ m
B. $40$ m
C. $20$ m ✓ Correct
D. $10$ m
Solution: $H = \frac{u^2}{2g} = \frac{400}{20} = 20$ m.
Q5 — Motion Under Gravity · easy · theory
A ball is thrown up at $30$ m/s. The time to reach the highest point is ($g = 10$ m/s²)
A. $9$ s
B. $3$ s ✓ Correct
C. $6$ s
D. $1.5$ s
Solution: $t = \frac{u}{g} = \frac{30}{10} = 3$ s.
Q6 — Motion Under Gravity · medium · theory
A ball thrown up at $20$ m/s returns to the point of projection. The total time of flight is ($g = 10$ m/s²)
A. $4$ s ✓ Correct
B. $8$ s
C. $2$ s
D. $1$ s
Solution: $T = \frac{2u}{g} = \frac{40}{10} = 4$ s (2 s up + 2 s down).
Q7 — Motion Under Gravity · easy · theory
At the highest point of a ball thrown vertically upward,
A. Velocity is maximum
B. Both velocity and acceleration are zero
C. Velocity is zero but acceleration is $g$ downward ✓ Correct
D. Acceleration reverses
Solution: The ball pauses momentarily but gravity never switches off — the famous conceptual trap.
Q8 — Motion Under Gravity · easy · theory
A ball is thrown up with speed $u$ and returns to the same point (no air resistance). Its return speed is
A. Zero
B. $u$ ✓ Correct
C. Greater than $u$
D. Less than $u$
Solution: Symmetry of free flight: it lands with the same speed it left with, directed downward.
Q9 — Motion Under Gravity · easy · theory
A stone is dropped from a tower of height $45$ m. The time it takes to reach the ground is ($g = 10$ m/s²)
A. $9$ s
B. $4.5$ s
C. $2$ s
D. $3$ s ✓ Correct
Solution: $45 = \frac{1}{2}\times10\times t^2 \Rightarrow t^2 = 9 \Rightarrow t = 3$ s.
Q10 — Motion Under Gravity · medium · theory
A body falls freely from rest. The distance it covers in the $3$rd second is ($g = 10$ m/s²)
A. $25$ m ✓ Correct
B. $45$ m
C. $15$ m
D. $30$ m
Solution: $s_n = \frac{g}{2}(2n-1) = 5\times5 = 25$ m.
Q11 — Motion Under Gravity · medium · numerical
A stone is dropped from $80$ m. Its speed on hitting the ground is ($g = 10$ m/s²)
A. $4$ m/s
B. $40$ m/s ✓ Correct
C. $20$ m/s
D. $80$ m/s
Solution: $v = \sqrt{2gh} = \sqrt{1600} = 40$ m/s (it takes 4 s).
Q12 — Motion Under Gravity · easy · theory
A ball is thrown up at $25$ m/s. Its height after $1$ s is ($g = 10$ m/s²)
A. $15$ m
B. $20$ m ✓ Correct
C. $25$ m
D. $30$ m
Solution: $h = ut - \frac{1}{2}gt^2 = 25 - 5 = 20$ m.
Q13 — Motion Under Gravity · medium · theory
A person in a freely falling lift experiences apparent
A. Weightlessness ✓ Correct
B. Double weight
C. Normal weight
D. Sideways force
Solution: Falling with acceleration $g$, the floor exerts no normal force — apparent weight is zero.
Q14 — Motion Under Gravity · easy · theory
One ball is dropped and another is thrown horizontally from the same height at the same moment. Which lands first? (ignore air)
A. The thrown one
B. Depends on their masses
C. The dropped one
D. Both land together ✓ Correct
Solution: Vertical motion is identical for both — horizontal velocity doesn’t affect fall time.
Q15 — Motion Under Gravity · medium · theory
A stone dropped from a height takes $3$ s to fall. The distance it falls in the LAST second is ($g = 10$ m/s²)
A. $15$ m
B. $20$ m
C. $25$ m ✓ Correct
D. $45$ m
Solution: Total $45$ m; in first $2$ s it falls $20$ m; last second: $45-20 = 25$ m.
Q16 — Motion Under Gravity · easy · theory
For a ball thrown vertically up (ignoring air), the time of ascent compared to the time of descent is
A. Equal ✓ Correct
B. Double
C. Greater
D. Smaller
Solution: Free flight is symmetric: same speeds at same heights, so equal times.
Q17 — Motion Under Gravity · medium · theory
A ball is thrown up at $20$ m/s. Its speed at HALF the maximum height is ($g = 10$ m/s²)
A. $20$ m/s
B. $10$ m/s
C. $10\sqrt{2}$ m/s ✓ Correct
D. $5\sqrt{2}$ m/s
Solution: $H = 20$ m; at $h = 10$: $v^2 = 400 - 2(10)(10) = 200 \Rightarrow v = 10\sqrt{2} \approx 14.1$ m/s.
Q18 — Motion Under Gravity · medium · theory
A stone is thrown up at $10$ m/s from the top of a $15$ m cliff. The time it takes to reach the ground below is ($g = 10$ m/s²)
A. $2$ s
B. $1$ s
C. $3$ s ✓ Correct
D. $1.5$ s
Solution: Taking down as positive: $15 = -10t + 5t^2 \Rightarrow t^2 - 2t - 3 = 0 \Rightarrow t = 3$ s.
Q19 — Motion Under Gravity · easy · theory
On the Moon, $g$ is about $\frac{1}{6}$th of Earth’s. A ball thrown up at the same speed there rises
A. $6$ times higher ✓ Correct
B. $\frac{1}{6}$th as high
C. The same height
D. $36$ times higher
Solution: $H = \frac{u^2}{2g}$: smaller $g$ (÷6) means larger $H$ (×6).
Q20 — Motion Under Gravity · medium · theory
A ball is thrown up at $40$ m/s. The distance it covers in the $4$th second is ($g = 10$ m/s²)
A. $5$ m ✓ Correct
B. $20$ m
C. $10$ m
D. $15$ m
Solution: $s_4 = u - \frac{g}{2}(2\times4-1) = 40 - 35 = 5$ m (it is nearly at the top at $t=4$ s).
Q21 — Motion Under Gravity · medium · numerical
A juggler throws balls up at $20$ m/s, tossing a new ball each time the previous one is at its highest point. How many balls are in the air at a time? ($g = 10$ m/s²)
A. $2$ ✓ Correct
B. $1$
C. $4$
D. $3$
Solution: Time to top $= 2$ s and flight time $= 4$ s: while one ball completes its flight, one more is launched — 2 aloft at any moment.
Q22 — Motion Under Gravity · easy · theory
The standard equations of motion under gravity assume
A. The height is large
B. The body is heavy
C. Nothing about air
D. Air resistance is negligible ✓ Correct
Solution: Free-fall formulas hold only when drag is ignored (or truly negligible).
Q23 — Motion Under Gravity · medium · theory
A body falling freely from rest covers a distance in the first second of ($g = 10$ m/s²)
A. $20$ m
B. $2.5$ m
C. $5$ m ✓ Correct
D. $10$ m
Solution: $h = \frac{1}{2}\times10\times1 = 5$ m.
Q24 — Motion Under Gravity · medium · theory
Two water drops fall from a tap $1$ s apart. As they fall, the separation between them
A. First increases then constant
B. Stays constant
C. Keeps increasing ✓ Correct
D. Decreases
Solution: The earlier drop is always faster ($v = gt$), so the gap grows continuously.
Q25 — Motion Under Gravity · easy · theory
The velocity–time graph of a body falling freely from rest is
A. A vertical line
B. A horizontal line
C. A straight line through the origin with slope $g$ ✓ Correct
D. A parabola
Solution: $v = gt$ — linear in time, starting from zero, slope $g$.
Q26 — Motion Under Gravity · easy · theory
A ball is thrown DOWNWARD at $5$ m/s from a height of $30$ m. The time to reach the ground is ($g = 10$ m/s²)
A. $3$ s
B. $2$ s ✓ Correct
C. $6$ s
D. $1.5$ s
Solution: $30 = 5t + 5t^2 \Rightarrow t^2 + t - 6 = 0 \Rightarrow t = 2$ s.
Q27 — Motion Under Gravity · easy · theory
The maximum height reached by a body projected vertically upward is proportional to
A. $u^2$ ✓ Correct
B. $u$
C. $u^3$
D. $\sqrt{u}$
Solution: $H = \frac{u^2}{2g} \propto u^2$: double the speed, four times the height.
Q28 — Motion Under Gravity · medium · theory
Ball A is dropped and ball B is thrown downward at $5$ m/s from the same height at the same time. Which hits the ground first?
A. Both together
B. B ✓ Correct
C. Depends on their masses
D. A
Solution: B starts with downward speed, stays ahead the whole way, and lands first. Mass is irrelevant.
Q29 — Motion Under Gravity · medium · theory
A ball thrown up returns to the thrower. Over the whole flight, its average VELOCITY is
A. $\frac{u}{2}$
B. $g$
C. Zero ✓ Correct
D. $u$
Solution: Displacement is zero (returns to start), so average velocity is zero — average speed is not.
Q30 — Motion Under Gravity · easy · theory
A ball is thrown up at $30$ m/s. Its velocity at $t = 4$ s is ($g = 10$ m/s²)
A. $10$ m/s upward
B. $70$ m/s
C. Zero
D. $10$ m/s downward ✓ Correct
Solution: $v = 30 - 40 = -10$ m/s: it topped out at 3 s and is now falling at 10 m/s.