Answer : Question 10

Question 10

a) i) Both the coin and feather fall due to the gravitational pull. In the lab, when they move through the air, the air resists against their motion. The air resistance depends on the shape of the body and velocity of the body. The feather has greater surface area than the coin. Hence the feather experiences greater air resistance and its acceleration decreases.

There is no air in the vacuum cylinder. Thus two objects move down without air

resistance and reach the bottom of the cylinder at the same time.

ii) Parachute-----payung terjun

b) i) arrange data :

m1 = 200kg, u=12m/s

m2 = 300kg, v= ?? ( tak tahu)

this is an …..inelastic collision…

m1u1 x m2u2 = (m1+m2)v………hey u2=0 since its not moving

200 x 12 = (200+3000)v

v = 0.75 m/s

ii) Loss of K.E = Work done against friction

Loss of K.E = ½ mv² = ½ x 3200 x 0.75² = 900 J .....all the K.E used to move the stomp

Work done = force(friction) x distance

900 = f x 0.2 …………..must change cm to m

f = 4500 N