Answer:
KE = 10530 J or 10.53 KJ
Explanation:
The formula for kinetic energy is KE = 1/2 mv^2
Let's apply the formula:
KE = 1/2 mv^2
KE = 1/2 (65kg) (18m/s)^2
KE = 10530 J or 10.53 KJ
Answer:
The effective spring constant of the firing mechanism is 1808N/m.
Explanation:
First, we can use kinematics to obtain the initial velocity of the performer. Since we know the angle at which he was launched, the horizontal distance and the time in which it's traveled, we can calculate the speed by:

(This is correct because the horizontal motion has acceleration zero). Then:

Now, we can use energy to obtain the spring constant of the firing mechanism. By the conservation of mechanical energy, considering the instant in which the elastic band is at its maximum stretch as t=0, and the instant in which the performer flies free of the bands as final time, we have:

Then, plugging in the given values, we obtain:

Finally, the effective spring constant of the firing mechanism is 1808N/m.
Answer:
31.1 N
Explanation:
m = mass attached to string = 0.50 kg
r = radius of the vertical circle = 2.0 m
v = speed of the mass at the highest point = 12 m/s
T = force of the string on the mass attached.
At the highest point, force equation is given as

Inserting the values

T = 31.1 N