Physics 9702/21 — October/November 2017

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

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Topics Physical Quantities and Units · Electricity · Dynamics · Kinematics · Superposition · Waves · +5 more

Q1Physical Quantities and UnitsDynamicsFree sample

(a)

The drag force $F_D$ acting on a sphere moving through a fluid is given by the expression

F_D = K\rho v^2

where $K$ is a constant,
$\rho$ is the density of the fluid
and $v$ is the speed of the sphere.

Determine the SI base units of $K$ .

base units = ______

(b)

A ball of weight $1.5\ \text{N}$ falls vertically from rest in air. The drag force $F_D$ acting on the ball is given by the expression in (a). The ball reaches a constant (terminal) speed of $33\ \text{m s}^{-1}$ .

Assume that the upthrust acting on the ball is negligible and that the density of the air is uniform.

For the instant when the ball is travelling at a speed of $25\ \text{m s}^{-1}$ , determine

(i)

the drag force $F_D$ on the ball,

$F_D$ = ______ $\text{N}$

(ii)

the acceleration of the ball.

acceleration = ______ $\text{m s}^{-2}$

(c)

Describe the acceleration of the ball in (b) as its speed changes from zero to $33\ \text{m s}^{-1}$ .

The rest of this paper

7 more questions

Q2Kinematics · Physical Quantities and Units8M
Q3Superposition · Waves9M
Q4Deformation of Solids5M
Q5D.C. Circuits3M
Q6Electric Fields · Work, Energy and Power · Electricity10M
Q7Electricity10M
Q8Particle Physics5M

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