Jayne lifts the barbell 120 cm upwards. She has a mass of 60kg. How much work does she do?

When u step on the brakes what energy transformation takes place describe the transformation

larisa [96]

Before you step on the brakes, the car has kinetic energy, when you step on the brakes, it turns the kinetic energy into heat (thermal energy). When it stops completely, it has potential energy. Hope this helped :)

5 0

2 years ago

A 124-kg balloon carrying a 22-kg basket is descending with a constant downward velocity of 20.0 m/ s. A I.O-kg stone is thrown

nadya68 [22]

(a) 296.6 m

The motion of the stone is the motion of a projectile, thrown with a horizontal speed of

$v_x = 15.0 m/s$

and with an initial vertical velocity of

$v_{y0} = -20.0 m/s$

where we have put a negative sign to indicate that the direction is downward.

The vertical position of the stone at time t is given by

$y(t) = h + v_{0y} t + \frac{1}{2}gt^2$ (1)

where

h is the initial height

g = -9.81 m/s^2 is the acceleration due to gravity

The stone hits the ground after a time t = 6.00 s, so at this time the vertical position is zero:

y(6.00 s) = 0

Substituting into eq.(1), we can solve to find the initial height of the stone, h:

$0 = h + v_{0y} y + \frac{1}{2}gt^2\\h = -v_{0y} y - \frac{1}{2}gt^2=-(-20.0 m/s)(6.00 s) - \frac{1}{2}(9.81 m/s^2)(6.00 s)^2=296.6 m$

(b) 176.6 m

The balloon is moving downward with a constant vertical speed of

$v_y = -20 m/s$

So the vertical position of the balloon after a time t is

$y(t) = h + v_y t$

and substituting t = 6.0 s and h = 296.6 m, we find the height of the balloon when the rock hits the ground:

$y(t) = 296.6 m + (-20.0 m)(6.00 s)=176.6 m$

(c) 198.2 m

In order to find how far is the rock from the balloon when it hits the ground, we need to find the horizontal distance covered by the rock during the time of the fall.

The horizontal speed of the rock is

$v_x = 15.0 m/s$

So the horizontal distance travelled in t = 6.00 s is

$d_x = v_x t = (15.0 m/s)(6.00 s)=90 m$

Considering also that the vertical height of the balloon after t=6.00 s is

$d_y = 176.6 m$

The distance between the balloon and the rock can be found by using Pythagorean theorem:

$d=\sqrt{(90 m)^2+(176.6 m)^2}=198.2 m$

(di) 15.0 m/s, -58.8 m/s

For an observer at rest in the basket, the rock is moving horizontally with a velocity of

$v_x = 15.0 m/s$

Instead, the vertical velocity of the rock for an observer at rest in the basket is

$v_y (t) = gt$

Substituting time t=6.00 s, we find

$v_y = (-9.8 m/s)(6.00 s)=-58.8 m/s$

(dii) 15.0 m/s, -78.8 m/s

For an observer at rest on the ground, the rock is still moving horizontally with a velocity of

$v_x = 15.0 m/s$

Instead, the vertical velocity of the rock for an observer on the ground is now given by

$v_y (t) = v_{0y} + gt$

Substituting time t=6.00 s, we find

$v_y = (-20.0 m/s)+(-9.8 m/s)(6.00 s)=-78.8 m/s$

6 0

2 years ago

If jack was traveling north 120 miles and it took him 3 hours to get there. what is the velocity that jack was traveling? is thi

Dimas [21]

Answers:

40 mp/h; Vector

Reason:

120/3 is 40 miles per hour.

Velocity is a vector measurement.

^.^

- Amanda

4 0

3 years ago

A car accelerates from rest at 3.00 m/second squared What is the velocity after 5 secs ? What is the displacement after 5 second

andrey2020 [161]

Explanation:

after 5 seconds, the velocity is (5s)(3m/s²) = 15m/s

The displacement after 5s is

x=vo + (1/2)at²

x = 0 + (1/2)(3m/s²)(5s)(5s)

x= 37.5 m

3 0

3 years ago

A farmer using sustainable agriculrural practices will a. use increased crop diversity and fewer off the farm resources in order

kati45 [8]

a. use increased crop diversity and fewer off the farm resources in order to reduce pressure on resources

Explanation:

A farmer using sustainable agricultural practices will use increased crop diversity and fewer off the farm resources in order to reduce dependency on other resources.

The major goal of sustainable agriculture is to cultivate plants and groom livestock in the best way that won't alter the environment.

This usually entail the cultivation of different crops.
Diversity of crops provides the means to sustain and retain soil fertility naturally without having to add fertilizers.
In animal husbandry, some of wastes are used on farm and the excesses from the farm are used to feed livestock.
Sustainable agriculture is a practice of self-reliant agriculture without infringing on the environment.

learn more:

Human impact on rainforest brainly.com/question/12095428

#learnwithBrainly

6 0

3 years ago