Kinetic energy = (1/2) (mass) x (speed)²
At 7.5 m/s, the object's KE is (1/2) (7.5) (7.5)² = 210.9375 joules
At 11.5 m/s, the object's KE is (1/2) (7.5) (11.5)² = 495.9375 joules
The additional energy needed to speed the object up from 7.5 m/s
to 11.5 m/s is (495.9375 - 210.9375) = <em>285 joules</em>.
That energy has to come from somewhere. Without friction, that's exactly
the amount of work that must be done to the object in order to raise its
speed by that much.
Answer: It should be the 3rd option down!
Explanation:
<h2>What is an electric fuse?</h2><h3>
Answer: Electric fuse is a safety device used to limit the current in an electric circuit which melts and breaks the circuit whenever there is an excess flow of current through the circuit.</h3><h2>What is the working principle of electric fuse?</h2><h3>An electric fuse is based on the principle of heating effect of electric current. It is made up of thin metallic wire of non-combustible material. A fuse is always connected between the ends of the terminal in a series connection with the circuit.</h3>
Use kinematic equations to solve:
1) yf = yo + vo*t + 1/2at²
yf = final height
yo = initial height
vo = initial velocity
a = acceleration
t = time
yf - yo = vo*t + 1/2at²
yf - yo = h
vo = 0
Thus,
h = 1/2at²
h = 1/2(9.8)(12)² = 705.6 m
2) vf = vo + at
vo = 0
Thus,
vf = at
vf = (9.8)(12) = 117.6 m/s
