Answer:
F=m x a
(F is force ,M is mass and A is acceleration)
in thisncase the Mass is given but we need to find ou the acceleration
Formula for acceleration-
a=(v - u)/t
(v is final velocity , u is initiatal velocity and t is time)
a = (0 - 80)/4
a= -80/4
a= -20
By substituting the values-
F= m x a
F= 1500 x -20
F=-30000N
Thus the force acted is -30000N
hope this helps
a. 27
after that all you need to do is use the work formula as you will be able to acheive results
A. compounds because the reactants of a double replacement reaction do not have charges
Answer:

Explanation:
<u>Diagonal Launch
</u>
It's referred to as a situation where an object is thrown in free air forming an angle with the horizontal. The object then describes a known path called a parabola, where there are x and y components of the speed, displacement, and acceleration.
The object will eventually reach its maximum height (apex) and then it will return to the height from which it was launched. The equation for the height at any time t is


Where vo is the magnitude of the initial velocity,
is the angle, t is the time and g is the acceleration of gravity
The maximum height the object can reach can be computed as

There are two times where the value of y is
when t=0 (at launching time) and when it goes back to the same level. We need to find that time t by making 

Removing
and dividing by t (t different of zero)

Then we find the total flight as

We can easily note the total time (hang time) is twice the maximum (apex) time, so the required time is

B) They are all sources of electricity
Hope it helps!!