15x 9.8 x .3 = 44.1
15 x 9.8 x 1 = 147
147 - 44.1 = 102.9J
102.9 J
Explanation:
Gas pedal is not required to used on friction less surface. On a friction less surface once the car is started and caused to move, car continues to move with same velocity as there is no opposing force. Therefore, no pressing of gas pedal required. However, this situation is not possible in real life, as friction is always present.
There's so much going on here, in a short period of time.
<u>Before the kick</u>, as the foot swings toward the ball . . .
-- The net force on the ball is zero. That's why it just lays there and
does not accelerate in any direction.
-- The net force on the foot is 500N, originating in the leg, causing it to
accelerate toward the ball.
<u>During the kick</u> ... the 0.1 second or so that the foot is in contact with the ball ...
-- The net force on the ball is 500N. That's what makes it accelerate from
just laying there to taking off on a high arc.
-- The net force on the foot is zero ... 500N from the leg, pointing forward,
and 500N as the reaction force from the ball, pointing backward.
That's how the leg's speed remains constant ... creating a dent in the ball
until the ball accelerates to match the speed of the foot, and then drawing
out of the dent, as the ball accelerates to exceed the speed of the foot and
draw away from it.
1 watt = 1 joule/sec
2,000 watts = 2,000 joules/sec
(2,000 joule/sec) x (120 sec)
= (2,000 x 120) (joule-sec/sec)
= 240,000 joules .
For a pipe open at both ends, fund frequency (Fo) given byFo = v /2L
v = velocity of sound = 340 m/s (at about 20ºC)
Fo = 340/2*5.34 = 31.8 Hz
While for the one closed at one end and open at the other end...
For a pipe open at one end, fund frequency (Fo) given byFo = v/4L
Fo = 340/4*5.34= 15.9 Hz
