Selina solutions
Our top 5% students will be awarded a special scholarship to Lido.

Chapter 3 Laws Of Motion | Exercise 3E

Question 44

A ball is thrown vertically upwards with an initial velocity of 49m/s. Calculate: (i) the maximum height attained, (ii) the time taken by it before it reaches the ground again. (Take g=9.8m/s^2)

Looking to do well in your science exam ?  
Learn from an expert tutor. Book a free class!

Given: initial velocity u=49m/s, g=9.8m/s^2

(i) Assume ‘h’ to be the height, velocity = 0m/s at the greatest height

We know from the equation of motion,

\begin{array}{l} v^{2}-u^{2}=2 g h \\ \Rightarrow 0-(49)^{2}=2(-9.8)(h) \\ \Rightarrow h=(49)^{2} / 19.6 \\ \Rightarrow h=122.5 m \end{array}

(ii) Time taken before the ball reaches the ground is given by t=2u/g

t=2(49)/9.8

= 10s

Set your child up for success with Lido, book a class today!

Our top 5% students will be awarded a special scholarship to Lido.

subject-cta

Question 44

A ball is thrown vertically upwards with an initial velocity of 49m/s. Calculate: (i) the maximum height attained, (ii) the time taken by it before it reaches the ground again. (Take g=9.8m/s^2)

Looking to do well in your science exam ? Learn from an expert tutor. Book a free class!

Given: initial velocity u=49m/s, g=9.8m/s^2

(i) Assume ‘h’ to be the height, velocity = 0m/s at the greatest height

We know from the equation of motion,

\begin{array}{l} v^{2}-u^{2}=2 g h \\ \Rightarrow 0-(49)^{2}=2(-9.8)(h) \\ \Rightarrow h=(49)^{2} / 19.6 \\ \Rightarrow h=122.5 m \end{array}

(ii) Time taken before the ball reaches the ground is given by t=2u/g

t=2(49)/9.8

= 10s

Our top 5% students will be awarded a special scholarship to Lido.

subject-cta
Connect with us on social media!
2021 © Quality Tutorials Pvt Ltd All rights reserved
`