1. vertical component can be found using the vertical height and initial velocity is zero. Ans : 25ms-1
ii) The component 34 sin @= 25 , hence angle @ = 47.3
b) The is rate of change of momentum .
F= m(change in vel) /t = 0.13 ( 34 - 2 ) / 0.95 = 4.4 N
c) using only energy consideration, account for the loss of ke of the stone. The water gain ke and pe .
2. The straight line passing through the origin shows that acc is proportional to displacement.
The negative grad shows that the dir of acc is opp the the displacement .
bi) When the sand lose contact with the plate, acc= g . The Weight is the resultant force that gives rise to acc a . mg = ma , hence a = g
ii) Read from graph the x when g = 9.81 ms-2. x = 3.8 mm
3. a) Equate centripetal acc to gravitational acceleration
Obtain the expression for the speed. subs the speed to otain the kinetic energy of the satellite .
11) gpe/ke = GMm/r divide by 1/2(GMm/r) = -2
b) Plot the graph of KE by using the Gpe value and dividing it by 2
ii) Read off the two values of GPE at the two distances. Half the GPE to obtain KE . Find the speed separately. Deduct to find change in speed.
4. a) current = power/ V
I = 5.62/ 4.5=1.25 A
ii) pd= IR , R = V/I = 4.5 /1.25 = 3.6 ohm
b) E = 4.5 + 1.25 (r) and E= 1.6(2.03 + r) equate the two equations.
r = 3.6 ohm
5. When temperature increase , electrons in valence band have sufficient energy to overcome band gap and are raised up to conduction band. This create increase in number of electrons in the CB and holes in the VB. More charge carriers contribute to the decrease in resistance.
6. a) Nuclei that emits particles like alpha , beta and gamma radiation is said to be radioactive.
bi) The decay constant is the fration of the nuclei that decay per unit time.
ii) decay constant = A/N = 1.26 x 105/ N =7.8 x 10-10 s-1
N can be obtained by dividing mass with 90u.
c) Activity would change considerably during the time of measurement if decay constant were large.
7. a) gradient indicates the rate. The rate of increase of radius is higher at the start and becomes lower at a later time.
ii) The volume of the room = 12x5x3= 180 m3. The radius would be 3.5 m . Check the time taken for the fire to fill the room would be 1 ms . Hence the fire ball spread the whole room too quickly and hence would be hazardous.
b) read off graph
d)i) the constant c may type of liquid or volatility of the liquid.
ii) Other situation like explosion of petrol tank in cars.
