Answer:
A. 20 N
Explanation:
the weight of book is 2×10= 20N
Answer:
The ball would hit the floor approximately
after leaving the table.
The ball would travel approximately
horizontally after leaving the table.
(Assumption:
.)
Explanation:
Let
denote the change to the height of the ball. Let
denote the time (in seconds) it took for the ball to hit the floor after leaving the table. Let
denote the initial vertical velocity of this ball.
If the air resistance on this ball is indeed negligible:
.
The ball was initially travelling horizontally. In other words, before leaving the table, the vertical velocity of the ball was
.
The height of the table was
. Therefore, after hitting the floor, the ball would be
below where it was before leaving the table. Hence,
.
The equation becomes:
.
Solve for
:
.
In other words, it would take approximately
for the ball to hit the floor after leaving the table.
Since the air resistance on the ball is negligible, the horizontal velocity of this ball would be constant (at
) until the ball hits the floor.
The ball was in the air for approximately
and would have travelled approximately
horizontally during the flight.
Answer:
72.22 N
Explanation:
F = weight
m = mass of body
M = mass of earth
R = radius of earth
G = universal constant of gravitation
F_1= 650 N
F_1 = GMm/R^2
two earth radius above the surface of the earth:
F_2= GMm/(3R)^2= GMm/9R^2= F_1/9= 650/9
=72.22 N
It says an object will remain at rest unless external forces act upon it.