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Markscheme for Worksheet #2
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AS and A Level Physics Original material © Cambridge University Press 2010 1
2 Marking scheme: Worksheet (AS) 1 C [1]
2 B [1]
3 D [1]
4 B [1]
5 C [1]
6 time
yin velocit changeonaccelerati = [1]
Acceleration is a vector. [1]
7 u = 0 v = 15 m s−1 a = ? t = 0.30 s
tuva −
= [1]
30.0015 −
=a [1]
a = 50 m s−2 [1]
8 a The object is travelling initially at 20 m s−1 and has a constant acceleration. [1]
b a = gradient of graph [1]
0.82035 −
=a [1]
a = 1.88 m s−2 2s m 9.1 −≈ [1]
c Distance = area under the graph [1]
distance = area of ‘trapezium’ = ( ) 0.8352021
×+ [1]
distance = 220 m [1]
9 a u = 22 m s−1 v = 5.0 m s−1 a = ? t = 6.0 s
tuva −
= [1]
0.6220.5 −
=a [1]
2s m 8.2 −−≈a (negative value → deceleration) [1]
b 22 5Average velocity
2+
= = 13.5 m s−1 [1]
c distance = average velocity × time distance = 13.5 × 6.0 [1] distance = 81 m [1]
2 Marking scheme: Worksheet (AS)
AS and A Level Physics Original material © Cambridge University Press 2010 2
10 a u = 0 v = ? a = 9.81 m s−2 t = 2.3 s v = u + at [1] v = 0 + 9.81 × 2.3 [1] v = 22.6 m s−1 1s m 23 −≈ [1]
b s = ? u = 0 a = 9.81 m s−2 t = 2.3 s 2
21 atuts += [1]
s = 0 + 21 × 9.81 × 2.32 [1]
m 26≈s [1]
11 s = 9.0 m u = 4.0 m s−1 v = ? a = 0.45 m s−2 v2
= u2 + 2as [1]
v2 = 4.02 + (2 × 0.45 × 9.0) = 24.1 [1]
v2 = 1s m 9.41.24 −≈ [1]
12 s = 20 m u = 45 m s−1 v = 0 a = ? v2
= u2 + 2as [1]
202450
2
222
×−
=−
=suva [1]
2s m 51 −−≈a [1]
13 a
Line of positive slope [1]
Correct labels on axes [1]
b s = area under the graph s = area of ‘larger’ rectangle − area of shaded triangle [1]
tvvts )(21∆−= [1]
∆v = at [1]
hence 2
21)(
21 atvttatvts −=−= [1]
14 During free fall: s = 6.0 m u = 0 v = ? a = 9.81 m s−2 v2 = u2 + 2as [1]
0.681.92 ××=v [1] v = 10.85 m s−1 [1]
During landing on soft ground: s = 0.085 m u = 10.85 m s−1 v = 0 a = ?
v2 = u2 + 2as ⇒ 085.0285.100
2
222
×−
=−
=suva [1]
2s m 690 −−≈a [1]
2 Marking scheme: Worksheet (AS)
AS and A Level Physics Original material © Cambridge University Press 2010 3
15 a Distance = area under graph from 4 s to 8 s = 21 (12 + 6.0) × 4.0 [1]
distance = 36 m [1] b Acceleration = gradient of graph at 12.5 s [1]
acceleration = 2013
=∆∆
tv [1]
acceleration = 0.65 m s−2 (allow ± 0.10 m s−2) [1]
c Constant acceleration of 1.5 m s−2 from 0 to 10 s [1] Acceleration gradually decreasing to zero after 10 s [1]
16 a uh = 6052
.
.ts= = 4.17 m s−1 [1]
b Vertically final velocity is zero as ball passes over cross-bar. vv = uv + at 0 = u – 9.81 × 0.60 [1] uv = 5.89 m s−1 [1]
c u2 = (uh2 + uv
2) = 5.892 + 4.172 [1] u = 7.21 m s−1 [1]
d tan θ =174895
b
v
.
.uu
= = 1.41 [1]
θ = 55º above the horizontal [1]