When an object falls or is dropped from rest it's initial velocity is zero.
Using the equations for a motion in straight line. I can find the time it takes to reach 3.0 m down (half way).
x = vt - 4.9t²
-3 = 0 - 4.9t²
-3/-4.9 = t²
0.6122 = t²
0.7825 sec = t
v = v - gt
v = 0 - 9.8(0.7825)
v = -7.67 m/s
the negative denotes downward direction.
You could also solve the problem using potential and kinetic energy.
Since it starts with maximum PE and gets converted to KE when it hits the ground. mgh = mv²/2
mass cancels, use 3 meters for the halfway distance
-9.8(-3) = v²/2
29.4 * 2 = v²
√(58.8) = 7.67 m/s downwards
The answer is B. Mohammed has less kinetic energy than Autumn. Why cuz its right.
Answer:
Because the angle of the sun moves/rotates in the summer, the sun's rays move their angle and impact the earth.
Acceleration = (change in speed) / (time for the change)
Change in speed = (speed at the end) minus (speed at the beginning)
Change in speed = (-58 m/s) minus (54 m/s)
Change on speed = -112 m/s
Acceleration = (-112 m/s) / (0.8 s)
Acceleration = -140 m/s²
