Answer:
(a) the runner's kinetic energy at the given instant is 308 J
(b) the kinetic energy increased by a factor of 4.
Explanation:
Given;
mass of the runner, m = 64.1 kg
speed of the runner, u = 3.10 m/s
(a) the kinetic energy of the runner at this instant is calculated as;
(b) when the runner doubles his speed, his final kinetic energy is calculated as;
the change in the kinetic energy is calculated as;
Thus, the kinetic energy increased by a factor of 4.
Answer:
Angular acceleration = 5 rad /s ^2
Kinetic energy = 0.391 J
Work done = 0.391 J
P =6.25 W
Explanation:
The torque is given as moment of inertia × angular acceleration
angular acceleration = torque/ moment of inertia
= 10/2= 5 rad/ s^2
The kinetic energy is = 1/2 Iw^2
w = angular acceleration/time
=5/8= 0.625 rad /s
1/2 × 2× 0.625^2
=0.391 J
The work done is equal to the kinetic energy of the motor at this time
W= 0.391 J
The average power is = torque × angular speed
= 10× 0.625
P = 6.25 W
The correct choice would be
B) The Sun’s mass is much greater than Earth’s
The sun as we know has greatest mass in our solar system and lighter objects tends to orbit around the heavier objects. the mass of earth is very much smaller as compared to that of the sun. hence the earth orbits around the sun due to the force of gravitational attraction between the two objects.
Objects have the same velocity only if they are moving at the same speed and in the same direction. Objects moving at different speeds, in different directions, or both have different velocities.
