Answer:
Any two forces acting on each other, which are not equal and opposite ( thereby causing motion ) are unbalanced forces.
Explanation:
Expierience
The initial height of the first body is given by:

where
g is the gravitational acceleration
t is the time it takes for the body to reach the ground
Substituting t=1 s, we find

The second body takes takes t=2 s to reach the ground, so it was located at an initial height of

The second body started its fall 1 second before the first body, therefore when the second body started its fall, the first body was located at its initial height, i.e. at 4.9 m from the ground.
Given that,
Height =1.5 m
Angle = 45°
We need to find the greater speed of the ball
Using conservation of energy


Here, initial velocity and final potential energy is zero.

Put the value into the formula




Hence, the greater speed of the ball is 5.42 m/s.
Answer:
a car
A sled sliding across snow or ice.
a ball down a hill
mercury
Explanation:
Answer:
0.143 m
Explanation:
The relationship between force applied on a string and stretching of the spring is given by Hooke's law:

where
F is the force exerted on the spring
k is the spring constant of the spring
x is the stretching of the spring from its equilibrium position
In this problem, we have:
F = 20 N is the force applied on the spring
k = 140 N/m is the spring constant
Solving for x, we find how far the spring will stretch:
