Forces And Newtons Laws Of Motion
A box rests on a horizontal table. Which set of forces should appear on a free-body diagram of the box?
Which statement correctly defines the centre of gravity of an extended rigid body?
A skydiver of mass 80 kg falls vertically. At one instant the upward drag force on her is 540 N. Taking g = 9.81 N kg⁻¹, calculate her acceleration at this instant.
A small dense ball falls through still air and reaches terminal velocity. Which statement correctly describes the forces and motion?
A passenger of mass 60 kg stands on a bathroom scale inside a lift that accelerates downward at 2.0 m s⁻². Taking g = 9.81 N kg⁻¹, calculate the reading on the scale.
Which statement correctly defines gravitational field strength at a point?
An astronaut has a weight of 686 N on Earth, where g = 9.81 N kg⁻¹. On the surface of the Moon, where g = 1.62 N kg⁻¹, what are her mass and weight?
In Core Practical 1, a student plots a graph of fall distance s on the y-axis against ½t² on the x-axis. Why does the gradient of this graph equal g?
In Core Practical 1, the electromagnet continues to grip the ball-bearing briefly after the current is switched off, while the electronic timer has already started. What effect does this have on the calculated value of g?
Why is an electronic timer, triggered by the switch and the trapdoor, used in Core Practical 1 rather than a hand-operated stopwatch?
Which statement is the most precise expression of Newton’s third law of motion?
Two forces form a Newton’s third law pair. Which combination of properties must they share?
A book rests in equilibrium on a horizontal table. Earth’s gravitational pull on the book acts downward (the book’s weight). Which force forms the Newton’s third law pair with this weight?
A helium balloon rises vertically through still air at constant velocity. Which statement correctly describes the forces acting on it?
A person standing in a stationary rowing boat steps forward off the bow onto a dock. The boat is observed to move backward as they step off. Which Newton’s third law explanation is correct?
Two metal spheres of different mass are released simultaneously from the same height in an evacuated tube. Which statement is correct and why?