Answer:
Torque = R X F = R * F sin theta
-f * 2R will exert an equal opposite torque
-f * 2 = F sin theta
f = -F sin theta / 2
Answer:

Explanation:
Regardless of the initial velocity of the pebble, the acceleration of the pebble is equal to the gravitational acceleration which is equal to 9.8 m/s2 towards downwards direction.
This can be shown by Newton's Second Law. According to the law, the net force applied on an object is equal to mass times acceleration of that object.
During the downward motion, the only force acting on the pebble is the gravitational force, hence its acceleration is equal to gravitational acceleration.
Solution :
Let
kg
m/s
Let
and
are the speeds of the disk
and
after the collision.
So applying conservation of momentum in the y-direction,





Therefore, the disk 2 have greater velocity and hence more kinetic energy after the collision.
Now applying conservation of momentum in the x-direction,




m/s
So, 
= 4.33 m/s
Therefore, speed of the disk 2 after collision is 4.33 m/s
Answer:
1.137278672 m/s
+5.9 cm or -5.9 cm
Explanation:
A = Amplitude = 6.25 cm
m = Mass of object = 225 g
k = Spring constant = 74.5 N/m
Maximum speed is given by

The maximum speed of the object is 1.137278672 m/s
Velocity is at any instant is given by

The locations are +5.9 cm or -5.9 cm