Answer:
619.8 N
Explanation:
The tension in the string provides the centripetal force that keeps the rock in circular motion, so we can write:
where
T is the tension
m is the mass of the rock
v is the speed
r is the radius of the circular path
At the beginning,
T = 50.4 N
v = 21.1 m/s
r = 2.51 m
So we can use the equation to find the mass of the rock:
Later, the radius of the string is decreased to
r' = 1.22 m
While the speed is increased to
v' = 51.6 m/s
Substituting these new data into the equation, we find the tension at which the string breaks:
It's Photoelectric Effect, I just a test with this same question. I am not good for explaining exactly how, but I was right.
Answer:
Option E is correct.
Time the ball remains in the air before striking the ground is closest to 3.64 s
Explanation:
yբ = yᵢ + uᵧt + gt²/2
yբ = 0
yᵢ = 2 m
uᵧ = u sinθ = 20 sin 60 = 17.32 m/s
g = -9.8 m/s², t = ?
0 = 2 + 17.32t - 4.9t²
4.9t² - 17.32t - 2 = 0
Solving the quadratic equation,
t = 3.647 s or t = -0.1112 s
time is a positive variable, hence, t = 3.647 s. Option E.
Answer:
the answer, the correct one is C
Explanation:
Let's propose the solution of this problem to know which explanation is correct, when the concha stick with the disc is an impulse exercise
I = ΔP
∫ F dt = pf-po
∫ F dt = m v_f - m v₀
Therefore, during the time that the contact lasts, a force is applied to the disk, which causes that if the amount of movement increases and therefore its speed increases, when the constant ceases the forces are reduced to zero and the disk no longer changes its momentum following with constant velocity.
When reviewing the answer, the correct one is C
