Answer:
Angular acceleration, is 
Explanation:
Given that,
Initial speed of the drill, 
After 4.28 s of constant angular acceleration it turns at a rate of 28940 rev/min, final angular speed, 
We need to find the drill’s angular acceleration. It is given by the rate of change of angular velocity.

So, the drill's angular acceleration is
.

where:
F - force
m - mass
a - acceleration
We transform this formula to get a:

Answer:
<h2>The angular velocity just after collision is given as</h2><h2>

</h2><h2>At the time of collision the hinge point will exert net external force on it so linear momentum is not conserved</h2>
Explanation:
As per given figure we know that there is no external torque about hinge point on the system of given mass
So here we will have

now we can say

so we will have


Linear momentum of the system is not conserved because at the time of collision the hinge point will exert net external force on the system of mass
So we can use angular momentum conservation about the hinge point
Weight = (mass) x (acceleration of gravity where the object is)
You didn't tell us WHERE the boulder is, so I have to assume that it's on Mars, where the acceleration of gravity is 3.71 m/s².
675,000 N = (mass) (3.71 m/s²)
Mass = (675,000 N) / (3.71 m/s²)
<em>Mass = 181,941 kilograms</em>
The same weight on Earth would suggest a mass of only 68,807 kg, so you can see how important it is to know where you are when you make your measurements.