**Answer:**

<h2>

**GRAVITY**</h2>

**Explanation:**

**When an object is dropped in the air , it experiences free fall.**

**Free fall is a special type of motion in which the only force acting upon an object is gravity. They do not encounter a significant force of air resistance**

**Answer:**

<h3>40.0 Joules. None of the answers is correct</h3>

**Explanation:**

Kinetic energy of an object is expressed as;

KE = 1/2mv² where;

m is the mass of the object

V is the velocity of the object.

Let Ma be the mass of the basketball and Mb be the mass of baseball.

If the mass of the basketball shown below is 4 times the mass of the baseball, then Ma = 4Mb

KE of the basket ball = 1/2MaVa²

**Va² = 2(KE)a/Ma ...... 1**

KE of the baseball = 1/2MbVb²

**Vb² = 2(KE)b/Mb .......... 2**

Since their velocities are the same, hence Va²= Vb²

2(KE)a/Ma = 2(KE)b/Mb

**Substituting Ma = 4Mb into the resulting expression.**

2(KE)a/4Mb = 2(KE)b/Mb

2(KE)a/4 = 2(KE)b

**Given Kinetic energy of baseball (KE)b = 10.0J, the expression becomes;**

2(KE)a/4 = 2(10)

2(KE)a = 4*20

2(KE)a = 80

(KE)a = 80/2

**(KE)a = 40.0J**

**Hence the kinetic energy of the basketball is 40.0Joules**

The beat frequency is the concept required to develop this process. The phenomenon is generated when you have two waves but their frequencies do not differ greatly. So the beat frequency will be the difference between those two waves. For this case we have the difference and one of the waves, therefore,

Our values are given as,

Using the formula of the frequency I will have,

Replacing we have,

The possible values are two: 1045Hz and 1055Hz

**Answer:**

Fractional error = 0.17

Percent error = 17%

F = 112 ± 19 N

**Explanation:**

Plug in the values to find the force:

F = (3.5 kg) (20 m/s)² / (12.5 m) = 112 N

Find the fractional error:

ΔF/F = Δm/m + 2Δv/v + Δr/r

ΔF/F = 0.1/3.5 + 2(1/20) + 0.5/12.5

ΔF/F = 0.17

Multiply by 100% to find the percent error:

ΔF/F × 100% = 17%

Solve for the absolute error:

ΔF = 0.17 × 112 N = 19 N

Therefore, the force is:

F = 112 ± 19 N