An object with a mass of 0 5kg, free fall for 2s, how much work is done by gravity How does the grav

Drop height h=square)=square)=20m

The work done by gravity w=mgh=

The gravitational potential energy of the object is reduced by 100j

Conservation by mechanical energy: The reduced gravitational potential energy is converted into the kinetic energy of the object.

So the kinetic energy of the object increases by 100j

Solution: The work done by gravity is: gh=mgh=mg(gt 2) 2=100 joules.

Gravitational potential energy: If the potential energy of the initial position is selected to be 0, then after 2s, the potential energy is reduced by 100 joules.

Kinetic energy: At the beginning the velocity is 0, the kinetic energy is 0, and after 2s, the gravitational potential energy decreases by 100 joules and translates into kinetic energy to increase by 100 joules.

The work done by gravity is mgh, h=1 2gt 2, i.e., h=20. The gravitational potential energy becomes less, and the gravitational potential energy is partially converted into kinetic energy. Thus the kinetic energy increases. The amount of kinetic energy increased is the same as the work done by gravity.

h= work done by gravity = 20*

The kinetic energy changed from zero to ( changed by 10

The velocity of two seconds is enough v=10*2=20, and the work kinetic energy theorem w=. The potential energy decreases by 100 J and the kinetic energy increases by 100 J.

(1.).Only gravity does the conservation of functional energy, the gravitational potential energy decreases, and the kinetic energy increases as, mgh=1 2mv 2

v=gt=10*2=20m/s

1/2mv^2=

2) The work done by gravity in the second second is equal to the work done without gravity in the time it falls for two seconds, minus the work done by gravity in one second.

i.e.: e=1 2mv 2-1 2mv 2=

After the object is released from a height of 30 meters, it falls freely under the action of gravity, s=1 2gt squared = 1 2 times 10 times 4=20m, but 20m is the falling distance, you need to use 30-20 to find the gravitational potential energy distance, after 2s, the object is 10 meters higher than the ground, and the gravitational potential energy ep=mgh=100j

The answers to the questions in the syllabus will not be wrong.

t=2s Falling height h=1 2*gt; 2=20m The first time to fall within two seconds, Qingchen Gaoyu Zen degree is h =15m (the ratio of equal time displacement from free fall is 1:3:5:7:.......)Available quickly).

The work done by gravity w=mgh=400j

Power p=mgh in the second second'/t = 2*10*15/1 w=300w

t=2sh=1 Egganda 2*gt; 2=20mh =15m (The ratio of the free fall is 1:3:5:7:.......)w=mgh=400j

p=mgh'T = 2*10*15 1 W=300W

1 then 2gt2 calculates the distance of the motion, multiplies gravity by the distance, and then uses the momentum theorem ft=mv to calculate the speed of the second second, and then multiplies the gravity by the speed to obtain the power.

The height of the fall in the second h=the height of the first 2 seconds of fall - the height of the first 1 s of fall = (1 2)g(2*2-1*1)=

The work of gravity in the second is w=gh=mgh=2*10*15=300j

The average power of gravity in the second second p=w 1s = 300 watts.

s=1 2at -- landing time t= 2s a= 45*2 10=3s

The speed when landing is v=at=10*3=30m s

g=1/2mv²=1/2*10000*30²=4500000jp=g/t=1500000

Gravity is still f=mg=100000n