Basics Of Ball Throwing

Classical Mechanics Level 2

In the absence of air resistance, a ball of mass $m$ is tossed upward to reach a height of $20 \text { m}$ . When it is $10 \text { m}$ in the air (half way up), what is the net force on the ball?

2m\vec{g}

m\vec{g}

\frac12 m\vec{g}

\frac14 m\vec{g}

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Nishant Shandilya
Mar 3, 2014

in the absence of resistance, net force will always be mg.

w=F.d => mgd = F.d => F=mg

Irshad Khan - 7 years, 3 months ago

if there was only gravitational force then the ball would have fall down .The force applied for tossing the ball should be greater than the gravitational force.so at maximum height the force is pure gravitational i.e. mg that's why the ball falls back. At a height half the maximum height the gravitational force should be less than mg otherwise the ball won't go further up

anu cs - 7 years, 3 months ago

at the time of tossing there was applied an impulse which gave a velocity to the ball. So the ball was set on a motion with a particular initial velocity and a constant force acting downwards (mg) causing a constant acceleration g downwards.

r meh - 7 years, 3 months ago

u r righ

Suraj Vajpayee - 7 years, 2 months ago

in the presence of air then the net force is ????

waqas khan - 7 years, 2 months ago

f=ma.. here mass-'m' and acceleration is gravity 'g'.. and so F=mg

Sri lakshmi - 7 years, 2 months ago

first of all , cause of air resistance is the gravitational force.... if there would be no resistance of air.. ball would move continously upward ??

Anuj Sharma - 7 years, 2 months ago

what about gavity,in outerspace planets do not experiance any resistance but are bounded by gravity of sun in their respective orbits than why so?

Nishant Sharma - 7 years, 2 months ago

I think ball could not have force mg only .. becuase the graviation force will balance the force on body at 20 mtr where the ball get stopped. it should be 2mg

Naveen Dubey - 7 years, 2 months ago

Deepan Kumar
Mar 11, 2014

only force acting on the ball is gravitational force,no other forces since we neglected air resistance,so finally there is only one force,there is no retarding force or additve force.........so always net force is mg

Sathi Nagi Reddy
Mar 11, 2014

The forces acting on an object in space is always gravitational force which is attracting it towards the earth. And air resistance will act opposite to its motion. He given that air resistance is negligible, so force acting is mg only

force is mg

Muhammad Babar - 7 years, 2 months ago

Suhan Roy
Mar 12, 2014

In the absence of air resistance,only the weight of the body is acting on it,irrespective of the height which the body has travelled.So, answer is mg.

Sunil Swain
Mar 12, 2014

in the absence of air resistance and at small hieghts the net force on the ball will be mg. It has got nothing to do with the hieght to which it is thrown or the velocity with which it is thrown.

Basics Of Ball Throwing

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