**Answer:**

**Explanation:**

opposite charges attract

same charges repel

neutral charges don't attract or repel

**Complete Question:**

A basketball player tosses a basketball m=1kg straight up with an initial speed of v=7.5 m/s. He releases the ball at shoulder height h= 2.15m. Let gravitational potential energy be zero at ground level

a) Give the total mechanical energy of the ball E in terms of maximum height hn it reaches, the mass m, and the gravitational acceleration g.

b) What is the height, hn in meters?

**Answer:**

a) Energy = mghₙ

b) Height, hₙ = 5.02 m

**Explanation:**

a) Total energy in terms of maximum height

Let maximum height be hₙ

At maximum height, velocity, V=0

Total mechanical energy , E = mgh + 1/2 mV^2

Since V=0 at maximum height, the total energy in terms of maximum height becomes

Energy = mghₙ

b) Height, hₙ in meters

mghₙ = mgh + 1/2 mV^2

mghₙ = m(gh + 1/2 V^2)

Divide both sides by mg

hₙ = h + 0.5 (V^2)/g

h = 2.15m

g = 9.8 m/s^2

V = 7.5 m/s

hₙ = 2.15 + 0.5(7.5^2)/9.8

hₙ = 2.15 + 2.87

hₙ = 5.02 m

It's a plain, not a lever

The most common group of silicates is quartz. Silicate minerals is the most abundant mineral found in the crust. About 90% of the crust contains these minerals. Silicate minerals includes quartz, mica, feldspar, pyroxene, amphobole and olivine. About 12% of these silicates is quartz.