Asked by Anonymous
If a 35 g arrow moving at 160 km/h penetrates a block of wood suspended by a rope, what impulse is delivered to the block? (Answer: 1.56kg * m/s)
What velocity will the wood block acquire if its mass is 7.0 kg? Ignore the mass of the arrow compared to that of the wood block. (Answer: 0.222m/s)
Please show all work on how to get those answers.
What velocity will the wood block acquire if its mass is 7.0 kg? Ignore the mass of the arrow compared to that of the wood block. (Answer: 0.222m/s)
Please show all work on how to get those answers.
Answers
Answered by
herp_derp
To the first problem, you need to convert all the numbers to the correct units.
35 kg = 0.035 kg
160 km/h = 44.44 m/s (Hint: to convert km/h quickly to m/s, divide by 3.6)
So, it is asking for the impulse which is
Imp = mv
Imp = (0.035 kg)(44.44 m/s) = 1.56 kg-m/s
To the second problem, you are trying to find the velocity assuming the impulse is the same.
v = p/m
v = (1.56 kg-m/s) / (7.0 kg) = 0.222 m/s
35 kg = 0.035 kg
160 km/h = 44.44 m/s (Hint: to convert km/h quickly to m/s, divide by 3.6)
So, it is asking for the impulse which is
Imp = mv
Imp = (0.035 kg)(44.44 m/s) = 1.56 kg-m/s
To the second problem, you are trying to find the velocity assuming the impulse is the same.
v = p/m
v = (1.56 kg-m/s) / (7.0 kg) = 0.222 m/s