Question

A man of mass 70kg ascends a flight of 36 steps each 20cm high. work done by the man against the gravitational force is (g=9.8ms-2)​

Answer 1

Answer:

• Work Done  (W) is 4939.2 Joules.

Given:

1. Mass of the Man (M) = 70 Kg.
2. No. of Steps (N) = 36 Steps.
3. Length of Each step (L) = 20 cm.

Explanation:

$\rule{300}{1.5}$

Firstly Finding The Height (h),

for Finding the Height we Know That,

⇒ Height (h) = No. of Steps x Length of step.

⇒ h = N x L

Substituting the Values,

⇒ h = 36 Steps x (20 cm)

⇒ h = 36  x (20 cm)

∵ [20 cm = 0.2 m]

Substituting,

⇒ h = 36  x 0.2

⇒ h = 72 x 10⁻¹

⇒ h = 7.2 Meters.

$\rule{300}{1.5}$

$\rule{300}{1.5}$

Now, From Work Done Formula,

⇒ W = Mgh

Here,

• M Denotes Mass of The Body.
• g Denotes Acceleration Due to Gravity.
• h Denotes Height to which the Body is Raisen.

⇒ W = Mgh

Substituting the Values.

⇒ W = 70 x 9.8 x 7.2

⇒ W = ( 70 x 9.8) x 7.2

⇒ W = ( 7 x 98) x 7.2

⇒ W = 686 x 7.2

⇒ W = 4939.2 J

∴ Work Done Against Gravitational Force is 4939.2 Joules.

$\rule{300}{1.5}$

Answer 2

Solution:

Given:

→ A man of mass 70kg ascends a flight of 36 steps each 20cm high. work done by the man against the gravitational force is (g = 9.8 ms - 2).

Find:

→ Find the work done against gravitational force.

Calculations:

→ h = N × L

Know terms:

→ Height = Total number of steps × Length of the step.

Adding the values to the equation:

→ h = 36 × (20 cm)

→ 20 cm

→ 0.2 m

Adding values to the equation:

→ h = 36 × 0.2

→ h = 72 × 10 ⁻¹

→ h = 7.2 m

Work done: This is a formula:

→ W = Mgh

Know terms:

• M = Mass of Body.
• g = Acceleration because to Gravity.
• h = Height of the Body.

Adding values to the Values:

→ W = ( 70 × 9.8) × 7.2

→ W = ( 7 × 98) × 7.2

→ W = (686 × 7.2)

→ W = 4939.2 J

Therefore, 4939.2 Joules is the work done against gravitational force.

#AnswerWithQuality

#BAL