Answer:
that would probably be Rock A is harder than Rock B
Explanation:
Because if Rock A can scratch Rock B then it obviously means that Rock A is harder.
Right?
Hope This Helps You Out♡
Answer:
K = 0.076 J
Explanation:
The height of the target, h = 0.860 m
The mass of the steel ball, m = 0.0120 kg
Distance moved, d = 1.50 m
We need to find the kinetic energy (in joules) of the target ball just after it is struck. Let t is the time taken by the ball to reach the ground.

Put all the values,

The velocity of the ball is :

The kinetic energy of the ball is :

So, the required kinetic energy is 0.076 J.
Explanation:
When a constant force acts upon an object the acceleration of the object varies inversely with its mass.

or

If m₁ = 21 kg, a₁ = 3 m/s², m₂ = 9 kg
We need to find a₂
So,

So, if mass is 9 kg, its acceleration is 7 m/s².
Answer:
C
Explanation:
Static electricity is what makes your hair stand up when you rub a balloon against it or gives you a shock from your doorknob. In static electricity, electrons are moved around mechanically (i.e. by someone rubbing two things together).
HOPE THIS HELPED AND LETTER D MADE ME LAUGH
Answer:

Explanation:
A differential equation that contain a term with di(t)/dt is in a RL circuit. Here we have

where vr is the voltage in the resistance, vi is the voltage in the inductance and vb is the source voltage. But also we have that

where L is the inductance of the circuit, r is the resistance an i is the current. By replacing we have the differential equation

I hope this is useful for you
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