7.(a)A heat resistant glass at 15℃ is fully filled with 250cm3 of glycerine.If the temperature increases to 25℃
how much glycerine overflows? The coefficient of volume expansion of glycerine is 5.1x 10-4K-1 and that
of heat resistant glass is 0.09x10-4K-1 . (4 marks )
(b)An object 5cm tall is 15 cm in front of a concave mirror of focal length 10cm.Can its image be receive on
a screen each side 9cm long? If so, in which position should the screen be placed? (4 marks )
8.(a) If the temperature of the medium is increased from 0℃ to 40℃, by what percentage has the velocity of
sound increased? (4 marks )
(b) A stone is dropped in a well whose water level is 20m down. How much time elapses until the sound of
the splash is heard? Assume the speed of sound to be 340ms-1. (4 marks )
The sum of two vectors , having unequal magnitudes, be equal to zero.
Force has both magnitude and direction.
Time is a scalar quantity.
If R ⃗= A ⃗+ B ⃗, then R ⃗ is the resultant vector of A ⃗and B ⃗.
If P ⃗= 1/3 Q ⃗ , then the magnitude of P ⃗ is less than that of Q ⃗.
Velocity vector v ⃗ and force F ⃗ may not be product.
The new vectors obtain from sub-dividing a vector is called vectors components.
Vector subtraction is, in fact vector addition.
For given diagram,
O ⃗+ P ⃗+ Q ⃗+ R ⃗ = 0