Question

a ball which is thrown upwards reaches the highest point in 4sec.Find the distance travelled by the ball​

Answer 1

Answer:

Distance travelled by the ball is 80m.

Answer 2

${\underline {\underline {\huge {\sf { Required \: Answer: } }}}}$

Given:

• Final velocity (v) = 0m/s

• Time taken (t) = 4 sec

To calculate:

• Distance/height (h)

Calculation:

Applying the 3rd equation of motion for freely falling bodies:

• ${\underline {\boxed {\Large {\bf {2gh = {v}^{2} - {u}^{2} } }}}}$

Where,

• g (acceleration due to gravity) = –10m/s² (as it is opposing respect to the gravitational force)

• h (height) = ?

• v (final velocity) = 0m/s

• u (initial velocity) = ?

So, we don't have initial velocity.Firstly let's calculate it:–

Applying the 1st equation of motion for freely falling bodies to calculate initial velocity:

• ${\underline {\boxed {\Large {\bf {v = u + gt} }}}}$

$\sf { ⇢ 0 = u + ( -10 \times 4) }$

$\sf { ⇢ 0 = u + (-40) }$

$\sf { ⇢ 0 = u - 40 }$

$\sf { ⇢ u = 0 + 40 }$

$\boxed { \sf { ⇢ u = 40m/s } }$

Now, substitute the values of all the given physical quantities in the 3rd equation of motion:

• ${\underline {\boxed {\Large {\bf {2gh = {v}^{2} - {u}^{2} } }}}}$

$\sf { ⇢2 \times (-10) \times h = {0 }^{2} - {40}^{2} }$

$\sf { ⇢-20 \times h = 0 - 1600 }$

$\sf { ⇢-20h = - 1600 }$

$\sf { ⇢h =\cancel{ \dfrac{ - 1600}{-20}} }$

$\boxed { \sf { ⇢h = 80m } }$

Therefore,the distance travelled by the ball is 80m.

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