From Mechanics
Solutions
1 (a)
| 02=72+2(−9.8)ss=4919.6=2.5Max Height = 5+2.5=7.5 m | (3 marks)
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1 (b)
| 0=7−9.8tt=79.8=0.714 s | (3 marks)
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| (6 marks)
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2 (a)
| T−800 9.8=800 0.2T=7840+160=8000 N | (3 marks)
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2 (b)
| T−800 9.8=800 (−0.2)T=7840−160=7680 N | (3 marks)
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2 (c)
| T=800 9.8=7840 N
| (1 mark)
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| (7 marks)
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3 (a)
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| (1 mark)
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3 (b)
| F=2 1.8=3.6 N
| (2 marks)
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3 (c)
| R=2 9.8=19.6 N
| (2 marks)
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3 (d)
| 3.6=19.6 =3.619.6=0.184 | (3 marks)
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| (8 marks)
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4 (a)
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| (1 mark)
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4 (b)
| R+Tsin30 =200 9.8R+0.5T=1960R=1960−0.5TAG | (3 marks)
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4 (c)
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F=Tcos30 Tcos30 =0.6(1960−0.5T)T(cos30 +0.3)=1176T=1176(cos30 +0.3)=1010 N
| (4 marks)
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| (8 marks)
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5 (a)
| 5i−2j=4i+3j+10aa=110(i−5j)= 0.1i−0.5j ms-2 | (3 marks)
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5 (b)
| r=(4i+3j)t+0.5(0.1i−0.5j)t2
| (2 marks)
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5 (c)
| r=(4t+0.05t2)i+(3t−0.25t2)j3t−0.25t2=0t(3−0.25t)=0t=0 or t=30.25=12 st=12 s | (3 marks)
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5 (d)
| v=(4+0.1t)i+(3−0.5t)j3−0.5t=0t=6 s | (3 marks)
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| (11 marks)
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AG: Answer Given in Question – Working must justify answer.