QUESTION 1
(a) (i) Define a scalar quantity and a vector quantity giving 3 examples of each quantity. (ii) Explain the meaning of " triangle of forces", support your answer with an appropriate example
(iii) A mass of 5kg hangs from two light strings of lengths 3m and 4m from two points at the same level and 5m apart. Find the tension in each of the strings. (acceleration due to gravity g = 9.81 ms-2)
(b) (i) Define the terms velocity and acceleration giving the units used
(ii) A ball is thrown vertically upwards from the ground with an initial velocity u. The time taken by the ball to reach a height "h" is "T1". The ball then takes a further time of "T2" to return to the ground. Find in terms of T1 , T2 and g (acceleration due to gravity),
(a) The initial velocity u
(b) The height "h"
(c) The maximum height "H" reached by the ball
(c) (i) A helicopter , flying in a straight line at a constant height of 500 m with a speed of 75 metres per second , drops an object. The object takes a time "T" to reach the ground and travels a horizontal distance "D" in doing so. Taking acceleration due to gravity g = 10 ms-2 and ignoring air resistance , what are the values of "T" and "D"?
(ii) State Newton?s Second Law of motion and explain what is meant by the " impulse" of a force
(d) A driver whose lorry will not start seeks a tow from a second driver. The towing vehicle accelerates slowly from rest with the tow-rope slack ; when the rope becomes tight, the towed lorry starts to accelerate and the towing vehicle moves with a constant speed of 0.8 metres per second until the towed lorry , of mass 1000 kg, achieves the same speed
(i) What is the change of momentum of the towed lorry?
(ii) The average tension in the rope may be assumed to be 4000 N during the acceleration of the towed lorry. How far does the towed lorry travel from rest before it reaches the speed of 0.8 metres per second?
(iii) How far does the towing vehicle travel in this time?
QUESTION 2
(a) (i) Explain the meaning of the term thermal equilibrium
(ii) State Zeroth law of thermodynamics and explain its usage in temperature measurements
(b) (i) A scale of temperature needs the following
1. A thermometric property
2. Two fixed points
3. A numerical scale
Give three examples of thermometric properties and the types of thermometers in which they are used
(ii) What features are desirable in a thermometric property if it is to be used for thermometry?
(iii) Give four advantages of the platinum resistance thermometer and explain why it is not suitable for measuring rapid changes in temperature
(b) Describe a "Thermoelectric thermometer" giving an appropriate diagram and explaining how temperature readings are obtained