Kinematics and Dynamics Questions and Answers

A body travelled in a straight line as shown in the velocity(v) - time(t) graph. Which distance(s)-time(t) graph correctly represents the motion of the body?

A missile is launched at an acute angle to the horizontal. Half-way through its trajectory, it explodes into several fragments due to entirely internal forces. Assuming free fall throughout, which statement is true?

In a perfectly elastic collision, which statement correctly describes momentum and energy conservation?

A tennis ball is dropped from a particular height h. The motion of the ball is monitored over three bounces. Which graph shows how the velocity (V) is varying with time (t)?

What is meant by an object's terminal velocity?

State the condition (in terms of the forces acting) under which an object travels at terminal velocity.

An object is projected vertically upward from the ground. Its velocity-time graph is a straight line from (0 s, 10 m/s) through (3 s, 0 m/s), continuing with the same slope to about (5 s, -6.7 m/s). Deduce from the graph the time at which the object reaches maximum height.

State the definition of linear momentum.

State the SI unit of linear momentum.

Which of the following is a plausible order-of-magnitude estimate for the wavelength of a gamma-ray photon?

What is meant by linear momentum?

State the principle of conservation of linear momentum, assuming no external force acts on a system of colliding bodies.

How is the principle of conservation of momentum linked to Newton's third law?

Sphere A (mass m) moving at speed 4u collides elastically with sphere B (mass 2m) moving at speed u in the same direction. What is meant by an elastic collision?

Which statement correctly distinguishes distance from displacement?

A ball is projected from a cliff 96 m high and lands 7.0 s later, a net 96 m below the launch point (air resistance negligible, $g = 9.81$ m s$^{-2}$). Using $s = ut - \frac{1}{2}gt^2$ with $s = -96$ m and $t = 7.0$ s (taking upward as positive), calculate the initial vertical velocity $u$ of the ball.

The ball's initial vertical velocity is $u \approx 20.6$ m s$^{-1}$ upward and $g = 9.81$ m s$^{-2}$. Calculate the time taken to reach the greatest height, where the vertical velocity is momentarily zero.

Which is a correct SI base quantity-unit pairing?

Which factor can make a dimensionally correct equation physically wrong?

Poiseuille's law for fluid flux Φ through a pipe is $\Phi = \frac{\pi}{8}\frac{\rho}{\eta}(P_1-P_2)\frac{R^4}{L}$, where ρ is density, η is viscosity (units Pa s), $P_1-P_2$ is a pressure difference, R is the pipe's internal radius and L is its length. Determine the base SI units of Φ.

A student repeats a measurement many times using an instrument that has not been checked for a zero error. Which statement correctly describes how random and systematic errors affect the set of readings obtained?

A ball has a diameter of about 2.15 mm. Name the laboratory instrument that should be used to measure this diameter to the nearest 0.01 mm.