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3 years ago

120 J of work was done to lift an object 6 m above

Physics

1 answer:

Slav-nsk [51]3 years ago

6 0

Answer:

The last option, 20 N and 2.04 kg

Explanation:

work = (force)(distance)

work = 120 joules

distance: 6 m

rearrange to find force:

120=(6)F

F= 120/6 = 20 Newtons.

Assuming its lifted from Earth's surface, the force of gravity will be 9.81 m/s^2. Let's find mass:

F=mg

m=F/g

m=(20)/(9.81)= 2.038 kg

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An arrow is launched upward with an initial speed of 100 meters per second (m/s). The equations above describe the constant-acce

ankoles [38]

Answer:

d=510.2m

t=10.2s

Explanation:

The formulas for accelerated motion are:

$v=v_0+at\\x=x_0+v_0t+\frac{at^2}{2}$

From them we can get $v^2=v_0^2+2ad$ .

We have:

$v-v_0=at\\t=\frac{v-v_0}{a}$

And substitute:

$x=x_0+v_0(\frac{v-v_0}{a})+\frac{a}{2}(\frac{v-v_0}{a})^2\\x-x_0=\frac{v_0(v-v_0)}{a}+\frac{(v-v_0)^2}{2a}$

We multiply both sides by 2a, and continue:

$2a(x-x_0)=2v_0(v-v_0)+(v-v_0)^2=2v_0v-2v_0^2+v^2+v_0^2-2vv_0=v^2-v_0^2$

Being d the displacement $x-x_0$ , we have $v^2=v_0^2+2ad$

For our exercise, we will write this as:

$d=\frac{v^2-v_0^2}{2a}$

And taking upwards direction positive and imposing final velocity 0m/s (for maximum height), we have:

$d=\frac{-v_0^2}{2a}=\frac{-(100m/s)^2}{2(-9,8m/s^2)}=510.2m$

For the time we use:

$t=\frac{v-v_0}{a}=\frac{-v_0}{a}=\frac{-(100m/s)}{(-9.8m/s^2)}=10.2s$

6 0

4 years ago

How much time does it take a trucker to deliver his shipment 480 km away travelling at an average speed of 120 km/hr?

kifflom [539]

Answer: time=4 hours

Explanation:

formula:

speed = $\frac{distance}{time}$

time = $\frac{distance}{speed}$

time= x

speed = 120km/hr

distance = 480 km

x = $\frac{480 km}{120km/hr\\}$

= $\frac{48km*hr}{12km}$

cut the zeros

and remove the signs

then

$\frac{48}{12}$ = 4

therefore, time taken to deliver the shipment by trucker is 4 hours

8 0

3 years ago

When two objects of different masses, different temperatures, and different sizes are placed in thermal contact, energy will alw

denpristay [2]

Answer:

a) from the hotter object to the cooler object

Explanation:

temperature moves by conduction, which is associated with the movement of atoms or molecules and the always move from hight temperatures to lower temperatures to attain thermal equilinrium of the system.

so when two objects are placed together and have different temperatures then the system is not in thermal equilibrium and to attain it, temperature can only move to coller object and not from the coller object according to thermodynamics.

6 0

3 years ago

Four football players are running down the field at the same speed. Player 1 weighs 180 lbs and is running toward the south goal

Serggg [28]

Player 2 because moment is mass times acceleration and since they are all going the same speed. Speed doesn't matter so the only thing that is left is mass/ weight and he has the most

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3 years ago

Some strongly electric fish will stun prey by generating an electric current that runs

Bezzdna [24]

Answer: when fish is stunning it's prey it's cause electric shock to the prey that's make it die and be able to be utilized by electric eel(fish generate electric surround)

4 0

3 years ago