# Thrust and Pressure Numericals for class 9 [solved]

Last updated on June 25th, 2023 at 01:29 pm

In this post, we have solved a set of **Thrust and Pressure Numericals for class 9**. Before that, we will go through the **formulas used** to solve these force and pressure problems.

**Formulas Used**

Pressure P = F/A = Force in perpedicular direction / Area

Pressure P = Thrust / Area

Force or thrust = Pressure x Area

=>F = PA

**Thrust and Pressure Numericals for class 9 **[with solution]

**(Q1)** Calculate the pressure exerted by a dancer weighing 600N standing on a single heel of area 1 cm^{2}. The surface of the dance floor is broken by pressures over 5 MPa. Will it be damaged by the dancer?

**Solution**:

Force F = 600 N

Area A = 1 cm^{2} = 0.0001 m^{2}

Pressure P = F/A

P = 600/0.0001 Pa = 6 x 10^{6} Pa = 6 MPa.

Answer: As the pressure exerted by the dancer is 6 MPa, which is more than the limit provided (5 MPa), hence the dance floor will be damaged by the dancer.

** (Q2) **What pressure is exerted by a force of 50000 N acting on 2.5 m^{2}?

**Solution:**

Force F = 50000 N

Area A = 2.5 m^{2}

Pressure P = F/A

P = 50000/2.5 Pa = 20000 Pa

**Force and Pressure Numericals for class 9 **

**(Q3)** A swimming pool has a level, horizontal, bottom. Its dimensions are 25 m by 5 m. The pressure of the water on the bottom is 15000 Pa. What total force does the water exert on the bottom of the pool? What is the weight of water?

**Solution:**

Area A = 25×5 = 125 m^{2}

Pressure P = 15000 Pa.

So, the total force exerted on the bottom of the pool:

F = PA = 15000 x 125 = 1875 x 10^{3} N

The weight of water is also 1875 x 10^{3} N

**(Q4)** An elephant has a mass of 5000 kg. The area of an elephant’s foot is 0.13 m^{2}. A woman has a mass of 60 kg. The area of her heel is 25 mm^{2}. Calculate the pressures exerted by the elephant and the woman.

**Solution:**

In the case of the Elephant:

mass = 5000 kg

area of foot = 0.13 m^{2}

Weight of the elephant = thrust = 5000 x 10 N = 50 000 N

Total area of 4 feet of the elephant = 4 x 0.13 m^{2} = 0.52 m^{2}

Hence, Pressure exerted by the elephant = thrust / area = 50000 / 0.52 = 96154 Pa

In the case of the woman:

mass =60 kg

area of foot = 25 mm^{2} = 25 x 10^{-6} m^{2}

Weight of the woman = thrust = 60 x 10 N = 600 N

Total area of 2 feet of the woman = 2 x 25 x 10^{-6} m^{2} = 50 x 10^{-6} m^{2}

Hence, Pressure exerted by the woman = thrust / area = 600 / [50 x 10^{-6}] = 12 x 10^{6} Pa = 12 MPa

Also, solve these **Pressure Practice Problems**