Rotational Motion Model Answers by Mr Harrison

Bad news!

MrHarrisonPhysics — 2024-09-24 10:11:54 UTC

You can only drop one mark across the whole paper to get 95% A1+

3b)

2024-09-24 10:13:32 UTC

F=(mv^2)/r

F= (3x10^4 x 230^2)/2x10^3

F= 793500

F= 794000N

Qu 1

MrHarrisonPhysics — 2024-09-24 10:15:39 UTC

1. (a) v = 6.2t + 4.1 {1} differentiate once

(b) 72 = 6.2t + 4.1 {1} sub in v=72 and solve

t = 11 s {1}

3c

2024-09-24 10:15:59 UTC

2ai)

2024-09-24 10:16:46 UTC

S=ut+1/2at^2

100=0+1/2a8^2

100+32a

a=3.1ms^-2

4b)

2024-09-24 10:17:41 UTC

2bi)

2024-09-24 10:17:57 UTC

The centripetal force required to keep the stone in place becomes too big (higher than frictional force holding the stone in place)

4a)(i)

2024-09-24 10:18:42 UTC

L=IW

L=5.1 x 1.7

L=8.67 kgm^2 rads^-1

2aii)

2024-09-24 10:18:54 UTC

distance = (1/100)*100=1%

Time = (0.4/8)*100=5%

Time^2 = 5*2 = 10%

ans = 10%

3a)

2024-09-24 10:18:59 UTC

The plane needs to be banked because it provides a centripetal force from the angle to keep it moving in a circular path. Rsin(angle)=Fc=mrw^2

2bii)

2024-09-24 10:21:24 UTC

F=mv^2/r

3=0.004v^2/0.3

0.9=0.004v^2

v=15ms^-1

2biii)

2024-09-24 10:22:34 UTC

at a tangent to the circle, at the point that the force exceeds the radial centripetal force.