Answer:
The platform move before coming to rest again 0.045 m far
Explanation:
Given
Ball is in motion
M (Platform mass + 2 people mass)
V (recoil velocity of the platform)
m (ball mass)
v (velocity ball)
MV + mv = 0
Distance of the platform movement is
t (time that the ball is in the air)
x = Vt
t = 
Knowing the platform and the ball are moving while the ball is in the air
x = 
Also knowing that

This way,
x =
= 
The minus sign means the displacement of the platform is in opposite direction to the displacement of the ball.
The 102N acting on the ropes being pulled by eric and kim have some of that force acting horizontally, and some of it vertically. By visualizing it as a right angled triangle, with the hypotenuse the length of the diagonal force, and each side the length of the horizontal and vertical forces, you can use trigonometry to calculate the length of the vertical force. You are told that it is at an angle of 30 with the vertical rope, therefore you know the length of the hypotenuse, and the angle between it and the vertical force, so using trig: (vertical force=x)
x/102=cos(30)
x=102*cos(30)
x=88.33
Therefore the diagonal ropes give a vertical force of 88.33N, and the centre rope, as it acts vertically, gives a vertical force of all 102N. The total:
88.33*2+102=278.66N
I don't know if this is very clear, I hope its good enough to help. If you don't understand, just ask, and I can answer any questions!!! :)
Answer:
option (i) is correct
Explanation:
as there is no air resistance, no force is acting on the object horizontally, but gravitational acceleration will obviously act, regardless of the air resistance... option (i) is correct
<span>So we need to put in the correct words to fill in the blanks. The FIRST law of thermodynamics states that energy can't be created or destroyed. It is a formulation of the law of conservation of energy modified for thermodynemical systems. Two natural sources of energy on Earth are the solar and wind. Also geothermal energy and hydropower are natural sources of energy. </span>
I believe this is right-
for the first question, it should be fluffy
and for the second it should be spot
potential energy is unused
kinetic energy is being used