Mass is a measure of how much matter an object contains, and weight is a measure of the force of gravity acting on the object.
A dummy is fired vertically upward from a canon with a speed of 40 m/s. How long is the dummy in the air? What is the dummies maximum height?
v=u-at
0=40-10xt
t=4 secs
height = ut-1/2at^2
height= 40x4-1/2x10x4^2
height = 160-5x16
height=160-80=80m
Answer:

Explanation:
At the corner of the square, the potential energy of interaction of other charges with the charge 2q is given by 
So

Also, since 
The initial energy of the system is given by;

Since 
, the final energy of the system is obtained by
From the law of conservation of energy, 
Therefore, 
Answer:
R^2 = 40^2 + 70^2 - 2(40)(70) cos 135°
Explanation:
The resultant connects the tail of the first vector to the head of the second vector (whose tail is at the head of the first vector). The three vectors form an obtuse triangle where the angle between the original direction and the second direction is 135°. The cosine factor in the Law of Cosines formula will be cos(135°), matching the second choice.