Answer:
A star's brightness also depends on its proximity to us. The more distant an object is, the dimmer it appears. Therefore, if two stars have the same level of brightness, but one is farther away, the closer star will appear brighter than the more distant star - even though they are equally bright!
Can I have brainliest?
Answer:
A real emf device has an internal resistance, but an ideal emf device does not.
Answer:
The mechanical energy of the ball-Earth-floor system the instant the ball left the floor is 7 Joules.
Explanation:
It is given that,
Initial gravitational potential energy of the ball-Earth-floor system is 10 J.
The ball then bounces back up to a height where the gravitational potential energy is 7 J.
Let U is the mechanical energy of the ball-Earth-floor system the instant the ball left the floor. Due to the conservation of energy, the mechanical energy is equal to difference between initial gravitational potential energy and the after bouncing back up to a height.
Initial mechanical energy is 10 + 0 = 10 J
Mechanical energy just before the collision is 0 + 10 = 10 J
Final mechanical energy, 7 + 0 = 7 J
Hence, the mechanical energy of the ball-Earth-floor system the instant the ball left the floor is 7 Joules.
Answer:
91.21
Explanation:
Kinetic energy =1/2 mv2 substitute the values I. E 1/2 *1 *4.5^2= 91.21
