Question

Three petrol kiosks, namely P, Q, R, lie along a straight road. The distances between each station are 1 km apart. A car initially at rest accelerates uniformly from its starting point o at time t = 0. It passes P after time tı, passes Q after a further 2 min travel from P and then passes R after a further 1.5 min travel from Q. Find - := iii. the time tu,, the car's acceleration, distance OP car's velocity at Q car's velocity at C. 3 V. Hint: Sketching a velocity-time graph will help you solve the problems. Question 5 Which one of the following three motions is not at constant acceleration? Explain your answer. i. A rock falling from a cliff. ii. An elevator moving from the second floor to the fifth floor making stops along the way. iii. A dish resting on a table

Please explain in detail thanks!

Answer 1

4.

exkm lkm € 1 km u=0 tot tot, +2 to it, +3.5 min. ® x= Oxt, + bath -o *+= 0(4,+2) + b 214+3) — 2+2 = 0(4,+3) = + alti+ 3G = 1=2at, +2a =) pat, = +1-29)

1 = % (1.5) (2+, +3.5) = 39 (2+, +7/2) 1 = 3 at, + 3 a 1= 22 (1-20) + 2 a 2 a= lg km min? do, at, = 1-2a (+, = 5/ min] so, x= ₃ (279) (34) = 20 km. 11 min

Velouty at Q = 18 at altta) [ = 2/9 (4.5) = 1 km min. / Ve= 0 + a[4,+3.5) Tue 2/9 X 6 = 4/3 Km/min An