Question
A ball is thrown vertically upwards. It returns 6 s later. Calculate : the initial velocity of the ball (Take $g=10 m s ^{-2}$ )
✓
Answer
Total time of journey $=6 s$
$
g =10 m / s ^2
$
Let $u ^{\prime}$ be the initial velocity.
Final velocity, $v=0$
Using the third equation of motion,
$v^2-u^2=2 g H$
or, $v^2-0=2(10)(45)$
or, $v^2=900$
or, $v=30 m / s$
$
g =10 m / s ^2
$
Let $u ^{\prime}$ be the initial velocity.
Final velocity, $v=0$
Using the third equation of motion,
$v^2-u^2=2 g H$
or, $v^2-0=2(10)(45)$
or, $v^2=900$
or, $v=30 m / s$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
State two differences between an electromagnet and a permanent magnet.
A car is moving with a uniform velocity $30 ms^{-1}$. It is stopped in 2 s by applying a force of 1500 N through its brakes. Calculate the following values: The retardation produced in car.
→What is the principle of a beam balance?
(i) The diameter of neck and bottom of a bottle are 2 cm and 10 cm, respectively. The bottle is completely filled with oil. If the cork in the neck is pressed in with a force of 1.2 kgf, what force is exerted on the bottom of the bottle? (ii) Name the law/principle you have used to find the force in part (a).
The boxes in figure (a, b, c) represent mirrors; insert a mirror which will reflect the incident ray as shown in the diagram.
A body of mass 70 kg , when completely immersed in water, displaces $20,000 cm^3$ of water. Find: (i) The weight of body in water and (ii) The relative density of material of the body.
→What do you understand by the terms
1. rest
2. motion? Support your answer by giving two examples each
1. rest
2. motion? Support your answer by giving two examples each
How can global warming can be reduced?
State Pascal's law.
A student calculates experimentally the value of density of iron as $7.4 gem ^{-3}$. If the actual density of iron is $7.6 gcm ^{-3}$, calculate the percentage error in experiment.
→