<span>anything harder than mohs scale 7 so eg Topaz, Corundum and diamond representing mohs scale 8 9 and 10 respectively.</span>
Answer:
5.7141 m
Explanation:
Here the potential and kinetic energy will balance each other

This is the initial velocity of the system and the final velocity is 0
t = Time taken = 0.04 seconds
F = Force = 18000 N
a = Acceleration
g = Acceleration due to gravity = 9.81 m/s²
Equation of motion

From Newton's second law

Squarring both sides

The height from which the student fell is 5.7141 m
A concave lens can only form a virtual image. The correct option among all the options that are given in the question is the third option or option "C". Concave lenses are mostly thinner in the middle compared to its edges. I hope that this answer has come to your help.
C. Combustion reaction.
These reaction are exothermic.
The reactions are:
2Mg + O2 -----> 2MgO
3Mg + N2 ------> Mg3N2
Answer:
The answer is h/4
Explanation:
When Peter collides with Fred, the collision is inelastic & they both proceed with a velocity of V/2.
let m represent the masses for Peter & Fred
v represent the initial velocity of Peter
V represent final velocity of both of them
mv + 3m × 0 = (m+m)V
V = v/2
Using the expression; H = v² / 2g .............Eqn 1
Upon substitution of V/2 into Eqn 1 above,
H = (V/2)² / 2g
H = (V²/4) ÷ 2g
Therefore height will be h/4