How is net force calculated when two forces act on an object in opposite directions?

If the ball reaches the ground in 8 seconds and the velocity of the ball before it hits the ground is 78.4. What is its accelera

Natasha2012 [34]

Answer:

9.8 m / s^2

Explanation:

Assuming free fall====> there is no initial downward/upward velocity

Assuming metric units 78.4 m/s

vf = a t

78.4 = a (8) shows a = 9.8 m/s^2

6 0

2 years ago

PLEASE HELP!!!!I IM GIVING BRAINLIEST!! If you answer this correctly ill answer some of your questions you have posted! (30pts)

maksim [4K]

Kinetic Energy

=>It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.

Potential Energy 

=>potential energy is the energy held by an

 object because of its position relative to other

 objects, stresses within itself, its electric

 charge, or other factors.

<h2>Difference:</h2>

=>Potential energy is a stored energy on the other hand kinetic energy is the energy of an object or a system's particle in Motion.

6 0

3 years ago

A 62-kg person jumps from a window to a fire net 20.0 m directly below, which stretches the net 1.4 m. Assume that the net behav

gayaneshka [121]

Answer:

a) x = 0.098

b) x = 2.72 m

Explanation:

(a) To find the stretch of the fire net when the same person is lying in it, you can assume that the net is like a spring with constant spring k. It is necessary to find k.

When the person is falling down he acquires a kinetic energy K, this energy is equal to the elastic potential energy of the net when it is max stretched.

Then, you have:

$K=U\\\\\frac{1}{2}mv^2=\frac{1}{2}kx^2$ (1)

m: mass of the person = 62kg

k: spring constant = ?

v: velocity of the person just when he touches the fire net = ?

x: elongation of the fire net = 1.4 m

Before the calculation of the spring constant, you calculate the final velocity of the person by using the following formula:

$v^2=v_o^2+2gy$

vo: initial velocity = 0 m/s

g: gravitational acceleration = 9.8 m/s^2

y: height from the person jumps = 20.0m

$v=\sqrt{2gy}=\sqrt{2(9.8m/s^2)(20.0m)}=14\frac{m}{s}$

With this value you can find the spring constant k from the equation (1):

$mv^2=kx^2\\\\k=\frac{mv^2}{x^2}=\frac{(62kg)(14m/s)^2}{(1.4m)^2}=6200\frac{N}{m}$

When the person is lying on the fire net the weight of the person is equal to the elastic force of the fire net:

$W=F_e\\\\mg=kx$

you solve the last expression for x:

$x=\frac{mg}{k}=\frac{(62kg)(9.8m/s^2)}{6200N/m}=0.098m$

When the person is lying on the fire net the elongation of the fire net is 0.098m

b) To find how much would the net stretch, If the person jumps from 38 m, you first calculate the final velocity of the person again:

$v=\sqrt{2gy}=\sqrt{2(9.8m/s^2)(38m)}=27.29\frac{m}{s}$

Next, you calculate x from the equation (1):

$x=\sqrt{\frac{mv^2}{k}}=\sqrt{\frac{(62kg)(27.29m/s)^2}{6200N/m}}\\\\x=2.72m$

The net fire is stretched 2.72 m

5 0

3 years ago

A Carnot engine operates between reservoirs at 600 and 300 K. If the engine absorbs 100 J per cycle at the hot reservoir, what i

PIT_PIT [208]

Answer:

W =50 J

Explanation:

given data:

T_h=600 k

T_L=300 k

Q_h=100 J

required:

W=??

solution:

║W║=║Q_h║(1-T_L/T_h)

=50 J

7 0

3 years ago

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Wyatt is moving a box with a mass of 37 kg a distance of 37 meters. Wyatt did 360 J of work in 2 minutes when moving the box. Wh

pentagon [3]

His power output was 3 Watt (360 Joule/120 seconds). The power output can be calculated by dividing the quantity of work by the amount of second needed for the activity and also by multiplying the force amount with the velocity of the activity. The power output usually used for measuring the ability of machine for doing its job.

7 0

3 years ago

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