The time after being ejected is the boulder moving at a speed 20.7 m/s upward is 2.0204 s.
<h3>What is the time after being ejected is the boulder moving at a speed 20.7 m/s upward?</h3>
The motion of the boulder is a uniformly accelerated motion, with constant acceleration
a = g = -9.8 
downward (acceleration due to gravity).
By using Suvat equation:
v = u + at
where: v is the velocity at time t
u = 40.0 m/s is the initial velocity
a = g = -9.8
is the acceleration
To find the time t at which the velocity is v = 20.7 m/s
Therefore,

The time after being ejected is the boulder moving at a speed 20.7 m/s upward is 2.0204 s.
The complete question is:
A large boulder is ejected vertically upward from a volcano with an initial speed of 40.0 m/s. Ignore air resistance. At what time after being ejected is the boulder moving at 20.7 m/s upward?
To learn more about uniformly accelerated motion refer to:
brainly.com/question/14669575
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Answer:
217.43298 m/s
Explanation:
= Mass of bullet = 19 g
= Mass of bob = 1.3 kg
L = Length of pendulum = 2.3 m
= Angle of deflection = 60°
u = Velocity of bullet
Combined velocity of bullet and bob is given by

As the momentum is conserved

The speed of the bullet is 217.43298 m/s
Radial acceleration is given by

where

then

Now

Using the relation


Putting into rpm
Answer:

Explanation:
From the question we are told that:
Mass 
Drop distance 
Generally the equation for Spring Constant is mathematically given by



<span>An event that breaks objects into smaller objects or pieces is called destructive force
</span><span>Tornadoes, Hurricanes, Earthquakes, Volcanoes, Tsunamis and more are some of examples
</span><span>Forces that wear down, destroy is right answer</span>