Physics 9702/42 — February/March 2016

Cambridge A-Level · A Level Structured Questions · worked solutions for every part, with the mark scheme

questions

100

marks

120

minutes

Topics Motion in a Circle · Medical Physics · Magnetic Fields · Nuclear Physics · Gravitational Fields · Thermodynamics · +9 more

Q1Gravitational FieldsMotion in a CircleFree sample

(a)

State Newton’s law of gravitation.

(b)

A satellite of mass $m$ has a circular orbit of radius $r$ about a planet of mass $M$ . It may be assumed that the planet and the satellite are uniform spheres that are isolated in space.

Show that the linear speed $v$ of the satellite is given by the expression

v = \sqrt{\frac{GM}{r}}

where $G$ is the gravitational constant.
Explain your working.

(c)

Two moons A and B have circular orbits about a planet, as illustrated in Fig. 1.1.

Fig. 1.1

Moon A has an orbital radius $r_A$ of $1.3 \times 10^8\ \text{m}$ , linear speed $v_A$ and orbital period $T_A$ .
Moon B has an orbital radius $r_B$ of $2.2 \times 10^{10}\ \text{m}$ , linear speed $v_B$ and orbital period $T_B$ .

(i)

Determine the ratio

$\frac{v_A}{v_B}$

ratio = ______

$\frac{T_A}{T_B}$

ratio = ______

(ii)

The planet spins about its own axis with angular speed $1.7 \times 10^{-4}\ \text{rad s}^{-1}$ .
Moon A is always above the same point on the planet’s surface.

Determine the orbital period $T_B$ of moon B.

$T_B$ = ______ $\text{s}$

The rest of this paper

12 more questions

Q2Thermodynamics · Ideal Gases11M
Q3Temperature · Alternating Currents9M
Q4Oscillations4M
Q5Communication4M
Q6Medical Physics8M
Q7Capacitance9M
Q8Electronics8M
Q9Magnetic Fields · Electric Fields · Motion in a Circle · Nuclear Physics11M
Q10Magnetic Fields5M
Q11Quantum Physics10M
Q12Medical Physics4M
Q13Nuclear Physics6M

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