Q226 · Practice questionTechnology-freeComplex familiar5 marks
QUESTION 226 (5 marks)
A 2 kg block is projected up a smooth plane at 6 m/s. The plane is inclined at 30 degrees to horizontal. Take g=10 m/s squared and up-plane displacement positive.
a)[2 marks]
Find normal reaction and along-plane acceleration.
b)[3 marks]
Find time and distance to rest, and first return time.
WORKED SOLUTION
5 marksPractice marking scheme
ANSWER
(a) N; m/s squared. (b) s, m, s.
Worked solution
(a) Normal force balances N. Along the plane, acceleration is . The smooth plane exerts no friction.
(b) gives rest at t=1.2. Displacement is then 3.6 m. Setting s=0 gives t=0 or 2.4, the latter being the first return.
Equivalent mathematically justified methods accepted.
Exact answers unless a decimal accuracy is specified.
Part a: Resolve perpendicular weight.
Part a: Resolve along-plane acceleration.
Part b: Find rest time.
Part b: Find rest displacement.
Part b: Find the first positive return time.
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