**Answer:**

**Explanation:**

m = Mass of block = 6 kg

F = Force on block = 5 N

= Coefficient of friction = 0

a = Acceleration of the block

From Newton's second law we have

The acceleration of the block is

**Answer:**

v = 0.999981c m/s

**Explanation:**

Using the time dilation equation

T = stationary time = 100 years

T₀ = 11/12 years = 0.917 years

v = speed of travel in the space = ?

c = speed of light = 3 * 10⁸ m/s

v = 299987395.57 m/s

v = 2.99 * 10⁸ m/s

v = 0.999981c m/s

The answer is A. A positive particle inside the nucleus

To solve this problem we start from the premise that energy is conserved. This means that the energy that the skier has at the beginning of the slope is equal to the energy he has at the end of the slope.

When the skier is at the top of the slope (point 1) his kinetic energy is minimal and his potential energy is maximum. Let's call to the energy in point 1.

Where:

mgh = potential energy

When the skier is at the lowest point of the slope (point 2) his kinetic energy is maximum and his potential energy is minimal. Let's call the energy in point 2.

Where :

= kinetic energy

= energy lost by friction

By the law of conservation of energy we know that:

So:

Where:

m = 40kg

v = 10 m/s

h = 12 m

g = 9.8

J