At the highest point: kinetic energy is 0 due to the speed is 0
So the total mechanical energy is 20
Assume no frictions present, then the mechanical energy is conserved
So at the lowest point, kinetic energy = mechanical energy - potential energy
Answer will be 20 - 0.5 = 19.5 J
I'm not sure what you were trying to put here
Answer:
615 N
Explanation:
If θ is the angle from vertical and T is the rope tension
θ = arcsin (2.0 / 3.5) = 34.85°
Summing vertical forces to zero
Tcosθ - mg = 0
T = 90.0(9.81) / cos34.85 = 1,075.85 N
Summing horizontal forces to zero
F - Tsinθ = 0
F = 1075.85sin34.85 = 1075.85(2.0/3.5) = 614.772... ≈ 615 N
Answer:
Cannonball b spends more time in the air than cannonball a.
Explanation:
Starting with the definition of acceleration, we have that:

Since both cannonballs will stop in their maximum height, their final velocity is zero. And since the acceleration in the y-axis is g, we have:

Now, this time interval is from the moment the cannonballs are launched to the moment of their maximum height, exactly the half of their time in the air. So their flying time t_f is (the minus sign is ignored since we are interested in the magnitudes only):

Then, we can see that the time the cannonballs spend in the air is proportional to the vertical component of the initial velocity. And we know that:

Finally, since
and
, we can conclude that:

In words, the cannonball b spends more time in the air than cannonball a.