Table A lists five separate events; Table B lists the three recognised categories of…
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics
Problem
Table A lists five separate events; Table B lists the three recognised categories of inertia. Using the letters P–T for the events and the numerals 1–3 for the categories, answer the questions that follow.
Table A (Events)
P. A coin placed on a playing card remains nearly at the same spot on the table when the card is flicked away quickly.
Q. Passengers feel an outward push when a car negotiates a right-hand bend at constant speed.
R. A football continues to roll along a level ground until slowed by friction.
S. A high jumper runs before taking the leap.
T. Luggage placed on the roof of a stationary bus tends to slip backward when the bus suddenly starts.
Table B (Categories of inertia)
1 Inertia of rest
2 Inertia of motion
3 Inertia of direction
(i) Match each event in Table A with the appropriate category (or categories, if more than one applies) from Table B. Write your answers in the form P – …, Q – …, R – …, S – …, T – …. Briefly justify each match in one or two sentences.
(ii) For event Q, derive an expression for the lateral force F that must act on a passenger of mass m travelling at speed v round a right-hand bend of radius r, assuming the passenger’s body initially tends to continue in a straight line.
(iii) A passenger of mass 60kg is travelling at 54kmh−1 round a bend of radius 40m. Using your expression from part (ii), calculate the magnitude of the lateral force required and state its direction relative to the centre of curvature.
(iv) State two practical measures adopted in automobile design to counteract the effects of the inertia identified in event Q.