Answer:
49 N
Explanation:
In order to move the box at constant speed, the acceleration of the box must be zero (a=0): this means, according to Newton's second law,
F = ma
that the net force acting on the box, F, must be zero as well.
Here there are two forces acting on the box in the horizontal direction while it is moving:
- The force of push applied by the guy, F
- The frictional force, 
For an object moving on a flat surface, the frictional force is given by
where
is the coefficient of friction
m is the mass of the box
g is the acceleration of gravity
So the equation of the forces becomes
And substituting:
We find the force that must be applied by the guy:
Total mass of the Sun = 2x10^30kg
<span>So 76% of that = (2x10^30kg)*(0.76) = 1.52x10^30kg ----> total amount of Hydrogen i</span><span>f only 12% of that is used for fusion, then (1.52x10^30kg)*(0.12) = 1.82x10^9kg</span>
Yes what do you need help on
Answer:
(a) 
(b) 
(c) 
Explanation:
(a) The total mechanical energy of the system is conserved.
(b) The conservation of energy states
(c) As explained in part (a) the total mechanical energy of the system is equal to the initial kinetic energy, since the potential energy of the system at that point is zero.
Answer:
= 308.5 N
Explanation:
acceleration of rocket for safe landing
= initial velocity
=final Velocity
m = mass of rocket
-5.625 
Upward force
F - mg = ma
F = ma+ mg
F = m(a+g)
m= mass
a = 5.625
g = 9.8
= 20(5.625 + 9.8)
= 308.5 N
