Answer:
t = 3.35 s
Explanation:
It is given that,
Mass of a pumpkin, m = 8 kg
It is dropped from a height of 55 m
We need to find the time taken by it to hit the ground.
Initial velocity of the pumpkin, u = 0
Using second equation of motion to find it as follows :
So, it will take 3.35 seconds to hit the ground.
The discovery of Uranus, Neptune, most asteroids, the moons of
any planet other than Earth, Pluto, and all the other dwarf planets,
required the invention and use of telescopes. Those objects are all
too dim to be seen with a bare naked human eye.
Saturn is bright and plainly visible with your eyes, if you know when
and where to look, and what you're looking at.
Answer:
(a) 8 m/s
(b) 5 s
Explanation:
(a)
Using,
V² = U²+2gh ......................... Equation 1
Where V = final velocity, U = Initial velocity, g = acceleration due to gravity on the surface of the moon, h = height reached.
Given: V = 0 m/s ( At it's maximum height), g = -1.6 m/s² ( as its moves against gravity), h = 20 m.
Substitute into equation 1
0 = U²+[2×20×(-1.6)]
-U² = - 64
U² = 64
U = √64
U = 8 m/s.
(b)
V = U +gt.................... Equation 2
Where t = time to reach the maximum height.
Given: V = 0 m/s ( At the maximum height), g = -1.6 m/s² ( Moving against gravity), U = 8 m/s.
Substitute into equation 2
0 = 8+(-1.6t)
-8 = -1.6t
-1.6t = -8
t = -8/-1.6
t = 5 s.
Answer: B
D makes no sense because energy is created so we can remove that. C also makes no sense because if energy is not created how did it get destroyed if there's no energy in the first place. This leaves us with a and B the correct answer is B because energy is created and cannot be destroyed.
