Answer:the answer is b
Explanation:
This is because in an ionic bond negative and positive bonds are present
<h2>Let us find the efficiency : Ans = 0.6</h2>
Explanation:
we know :
efficiency = output/input
We also know that :
output = m x g x h
where :
m = mass of body
g = acceleration due to gravity
h = height of body from floor
Thus, output = 0.6 x 10 x 1.2 = 7.2J
Similarly ,input = 0.6 x 10 x 2 = 12J
Thus efficiency = 7.2/12 = 0.6
Answer: 1.77 s
Explanation: In order to solve this problem we have to use the kinematic equation for the position, so we have:
xf= xo+vo*t+(g*t^2)/2 we can consider the origin on the top so the xo=0 and xf=29 m; then
(g*t^2)/2+vo*t-xf=0 vo is the initail velocity, vo=7.65 m/s
then by solving the quadratric equation in t
t=1.77 s
Answer:
The spring force constant is
.
Explanation:
We are told the mass of the ball is
, the height above the spring where the ball is dropped is
, the length the ball compresses the spring is
and the acceleration of gravity is
.
We will consider the initial moment to be when the ball is dropped and the final moment to be when the ball stops, compressing the spring. We supose that there is no friction so the initial mechanical energy
is equal to the final mechanical energy
:

Initially there is only gravitational potential energy because the force of the spring isn't present and the speed is zero. In the final moment there is only elastic potential energy because the height is zero and the ball has stopped. So we have that:

If we manipulate the equation we have that:



