Question

the body dropped freely from a certain height reaches the ground in 4s . the average velocity during fall is (g = 10m/s2​

Answer 1

Given

• A body is dropped from a certain height
• Initial Velocity = 0 m/s
• Time = 4 sec
• Gravitational Acceleration = 10 m/s²

To Find

• The average velocity during the fall

Solution

● s = ut + ½at² [Second Equation of Motion]

● Avg Velocity = Total Displacement/Total Time

● Here we shall find find the distance covered using the second equation of motion, as the body is falling the distance would be equal to the displacement of the body. And the total time is equal to 4 seconds. Simple substitution would get us our answer!!

✭ Distance Covered :

→ s = ut + ½at²

→ s = 0 × 4 + ½ × 10 × 4²

→ s = 0 + 5 × 4²

→ s = 0 + 5 × 16

→ s = 80 m

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✭ Average Velocity :

→ Avg Velocity = Total Displacement/Total Time

→ Avg Velocity = 80/4

→ Avg Velocity = 40 m/s

∴ Average Velocity of the body during the fall is 40 m/s

Answer 2

Answer:

Given :-

• Time = 4 sec
• Initial velocity = 0 m/s
• Gravity (due to acceleration) = 10 m/s²

To Find :-

Average velocity

Solution :-

So, for finding average velocity we must first find the distance travelled by body

s = ut+ ½at²

s = 0 × 4 + ½ × 10 × 4²

s = 0 + ½ × 10 × 16

s = 0 + 80

S = 80 m

Therefore, Distance travelled = 80 m

Now,

Let's find average velocity

$\bf \: avg. \: Velocity = \frac{Displacement}{Time}$

Avg velocity = 80/4

Avg velocity = 20 m/s