A projectile must have 150 kJ of kinetic energy to break through a city wall. Which of the following projectiles will break through the wall?
A. Mass = 100 kg; speed = 55 m/s
B. Mass = 150 kg; speed = 42 m/s
C. Mass = 200 kg; speed = 36 m/s
D. All of the above

A. Mass = 100 kg; speed = 55 m/s

Explanation:

The kinetic energy of an object is the energy that an object possessed due to its motion.

It is given by:

where

m is the mass of the object

v is its speed

Here we have to compare the kinetic energy of the three projectiles.

For projectile A:

A. Mass = 100 kg; speed = 55 m/s

So its KE is

For projectile B:

B. Mass = 150 kg; speed = 42 m/s

So its KE is

For projectile C:

C. Mass = 200 kg; speed = 36 m/s

So its KE is:

So, only projectile A has enough energy (150 kJ) to break the wall.

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

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