Use the law of conservation of momentum. Since the momentum is a linear measure, we can treat each of the dimension separately:
i-direction:
j-direction:
Answer: Final velocity is: (10i + 15j) m/s
Change in the kinetic energy:
Answer: The system lost 500J worth of kinetic energy in the collision
Answer:
a) 0.31 rad/s
b) 100 J
c) 6.67 W
Explanation:
(a) the force would generate a torque of:
According to Newton 2nd law, the angular acceleration would be
It starts from rest, then after 15s it would achieve a speed of
(b) The distance angle swept by it is:
Hence the work by the child
c) Average power to work per time unit
NB: The diagram of the pulley system is not shown but the information provided is sufficient to answer the question
Answer:
Power = 2702.56 W
Explanation:
Let the power consumed be P
Energy expended = E = mgh
height, h = 5 m
E = 80 * 9.8 * 5
E = 3920 J
To calculate the time, t
From F = ma
F = 900 N
900 = 80 a
a = 900/80
a = 11.25 m/s²
From the equation of motion,
The drill head starts from rest, u = 0 m/s
Power, P = E/t
P = 3920/0.0.943
P = 4157.79 W
But Efficiency, E = 0.65
P = 0.65 * 4157.79
Power = 2702.56 W