The answer is above but I don't know if it's correct.
Answer:
U = √Rg/sin2θ
Explanation:
Using the formula for "range" in projectile motion to derive the average speed before the ball hits the ground.
Range is the distance covered by the body in the horizontal direction from the point of launch to the point of landing.
According to the range formula,
R = U²sin2θ/g
Cross multiplying we have;
Rg = U²sin2θ
Dividing both sides by sin2θ, we have;
U² = Rg/sin2θ
Taking the square root of both sides we have;
√U² = √Rg/sin2θ
U = √Rg/sin2θ
Therefore, his average speed if he is to meet the ball just before it hits the ground is √Rg/sin2θ
From convection of magma under the earths crust makes the plates slowly move and as they move over time they build up potential energy from the different plates grinding against each other and after so long the plates will lose there grip on each other and release the potential energy they've been building up for so long as kinetic energy causing what you know as an earthquake hope this helps please give brainliest
Answer:

Explanation:
Work is energy transferred when an object is moved. It is the product of force and distance.

John did 3.2 Joules of work or 3.2 Newton meters of work (the units are equivalent). The window shade was lowered a distance of 0.8 meters.
Substitute the values into the formula.

We are solving for the force, so we must isolate the variable F. It is being multiplied by 0.8 meters. The inverse operation of multiplication is division, so divide both sides of the equation by 0.8 m.

The units of meters cancel.


John must exert <u>4 Newtons of force.</u>