IB Physics SL A.1 Kinematics Question Bank

Practise IB Physics SL A.1 by translating position, velocity and acceleration between words, graphs and equations, including projectile components.

Exam points

interpret position, velocity and acceleration graphs using gradients, areas and vector signs
select and apply constant-acceleration equations with signed quantities and SI units
resolve projectile components and analyse changing acceleration or terminal speed from data

Covered syllabus points

A.1.1—Position, velocity and acceleration A.1.2—Velocity and acceleration rates A.1.3—Displacement A.1.4—Distance and displacement A.1.5—Instantaneous and average values A.1.6—Uniform acceleration equations A.1.7—Uniform vs non-uniform acceleration A.1.8—Projectile components A.1.9—Fluid resistance on projectiles

[Maximum number: 4]

A ball of mass 0.250 kg is released from rest at time t=0, from a height H above a horizontal floor.

Figure for Question A.1 Kinematics question 1 — IB Physics SL

The graph shows the variation with time t of the velocity v of the ball. Air resistance is negligible. Take $g=-9.80 \mathrm{~ms}^{-2}$ . The ball reaches the floor after 1.0 s .

(a)

Determine H.

[ 1 ]

$H=\ll \frac{1}{2} g t^{2} \Rightarrow>4.9 \ll \mathrm{~m} \gg$

Marking guidance:

Accept other methods as area from graph, alternative kinematics equations or conservation of mechanical energy.

Award [1] for a bald correct answer in the range 4.9-5.1

Award [0] if time used is different than 1.0 s

(b)

Label the time and velocity graph, using the letter M , the point where the ball reaches the maximum rebound height.

[ 1 ]

M at $1.6 \mathrm{~s}$

(c)

State the acceleration of the ball at the maximum rebound height.

[ 1 ]

« $g=>9.80<\mathrm{ms}^{-2} \gg$

Marking guidance:

Accept 9.81, 10 or a plain "g" Ignore sign if provided.

(d)

Draw, on the axes, a graph to show the variation with time of the height of the ball from the instant it rebounds from the floor until the instant it reaches the maximum rebound height. No numbers are required on the axes.

[ 1 ]

[Maximum number: 2]

A toy rocket is made from a plastic bottle that contains some water.

Air is pumped into the vertical bottle until the pressure inside forces water and air out of the bottle. The bottle then travels vertically upwards.

Figure for Question A.1 Kinematics question 2 — IB Physics SL

The air-water mixture is called the propellant.
The variation with time of the vertical velocity of the bottle is shown.

The bottle reaches its highest point at time $T_{1}$ on the graph and returns to the ground at time $T_{2}$ . The bottle then bounces. The motion of the bottle after the bounce is shown as a dashed line.

Estimate the acceleration of the bottle when it is at its maximum height.

Attempt to calculate gradient of line at $t=1.2 \mathrm{~s}$

«-» 9.8 « $\mathrm{m} \mathrm{s}^{-2}$ » (accept 9.6-10.0)

[Maximum number: 8]

This question is in two parts. Part 1 is about kinematics and gravitation. Part 2 is about radioactivity.
Part 1 Kinematics and gravitation
A ball is released near the surface of the Moon at time t=0. The point of release is on a straight line between the centre of Earth and the centre of the Moon. The graph below shows the variation with time t of the displacement s of the ball from the point of release.

Figure for Question A.1 Kinematics question 3 — IB Physics SL

(a)

State the significance of the negative values of s.

[ 1 ]

(b)

Use the graph to

[ 3 ]

(i)

estimate the velocity of the ball at $t=0.80 \mathrm{~s}$ .

[ 3 ]

tangent drawn to curve at 0.80 s ;
correct calculation of gradient of tangent drawn;
$-1.3 \pm 0.1 \mathrm{~m} \mathrm{~s}^{-1}$ or $1.3 \pm 0.1 \mathrm{~m} \mathrm{~s}^{-1}$ downwards;
or
correct coordinates used from the graph; substitution into a correct equation;
$-1.3 \pm 0.1 \mathrm{~m} \mathrm{~s}^{-1}$ or $1.3 \pm 0.1 \mathrm{~m} \mathrm{~s}^{-1}$ downwards;

(c)

Calculate the speed of an identical ball when it falls 3.0 m from rest close to the surface of Earth. Ignore air resistance.

[ 1 ]

$\quad 7.7 \mathrm{~m} \mathrm{~s}^{-1}$ ;

(d)

Sketch, on the graph, the variation with time t of the displacement s from the point of release of the ball when the ball is dropped close to the surface of Earth. (For this sketch take the direction towards the Earth as being negative.)
Part 2 Radioactivity

Two isotopes of calcium are calcium-40 $\left({ }_{20}^{40} \mathrm{Ca}\right)$ and calcium-47 $\left({ }_{20}^{47} \mathrm{Ca}\right)$ . Calcium-40 is stable and calcium-47 is radioactive with a half-life of 4.5 days.

[ 3 ]

Curve permanently below Moon curve.
Smooth parabola (judge by eye).
Line passing through $s=-3.00\ ext{m}, t=0.78\ ext{s}$ or $s=-3.50\ ext{m}, t=0.84\ ext{s}$ ( $\pm 1\ ext{mm}$ ).

Figure for Answer to Question (d) — IB Physics SL

All question bank results loaded

Covered syllabus points

A.1 Kinematics question 1

Question (a)

Question (b)

Question (c)

Question (d)

A.1 Kinematics question 2

A.1 Kinematics question 3

Question (a)

Question (b)

Question (i)

Question (c)

Question (d)