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Ray Of Light [21]

3 years ago

5

A package rests on the floor of an elevator that is rising with constant speed. the elevator exerts an upward normal force on th

e package, and hence does positive work on it.why doesn't the kinetic energy of the package increase?

1 answer:

Tomtit [17]3 years ago

6 0

Because the actual package isn't moving so the gravitational potential energy stays the same. kinetic energy is gained through motion of the object not the motion of the surroundings of the object so
unless the package is falling out of a window its losing gravitational potential energy and gaining kinetic energy. hope this helps :-)

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Which of the following would be the SI unit to use in measuring the temperature of hot liquid

GREYUIT [131]

Answer:

Kelvin

Explanation:

The SI unit to use in measuring the temperature of hot liquid is kelvin (K)

7 0

3 years ago

an object traveling 200 feet per second slows to 50 feet per second in 5 seconds. Calculate the acceleration of the object

emmainna [20.7K]

Answer:

The acceleration of the object is $-30\ m/s^2$

Explanation:

Given:

Initial velocity of object $v_i$ = 200 feet/second

Final velocity of object $v_f$ = 50 feet/second

Time of travel = 5 seconds

To calculate acceleration of the object we will find the rate of change of velocity with respect to time.

So, acceleration $a$ is given by:

$a=\frac{v_f-v_i}{t}$

where $v_f$ represents final velocity, $v_i$ represents initial velocity and $t$ is time of travel.

Plugging in values to evaluate acceleration.

$a=\frac{50-200}{5}$

$a=\frac{-150}{5}$

$a=-30\ m/s^2$

The acceleration of the object is $-30\ m/s^2$ (Answer). The negative sign shows the object is slowing down.

4 0

4 years ago

Vector A has a magnitude of 50 units and points in the positive x direction. A second vector, B , has a magnitude of 120 units a

Alex Ar [27]

A) Vector A

The x-component of a vector can be found by using the formula

$v_x = v cos \theta$

where

v is the magnitude of the vector

$\theta$ is the angle between the x-axis and the direction of the vector

- Vector A has a magnitude of 50 units along the positive x-direction, so $\theta_A = 0^{\circ}$ . So its x-component is

$A_x = A cos \theta_A = (50) cos 0^{\circ}=50$

- Vector B has a magnitude of 120 units and the direction is $\theta_B = -70^{\circ}$ (negative since it is below the x-axis), so the x-component is

$B_x = B cos \theta_B = (120) cos (-70^{\circ})=41$

So, vector A has the greater x component.

B) Vector B

Instead, the y-component of a vector can be found by using the formula

$v_y = v sin \theta$

Here we have

- Vector B has a magnitude of 50 units along the positive x-direction, so $\theta_A = 0^{\circ}$ . So its y-component is

$A_y = A sin \theta_A = (50) sin 0^{\circ}=0$

- Vector B has a magnitude of 120 units and the direction is $\theta_B = -70^{\circ}$ , so the y-component is

$B_y = B sin \theta_B = (120) sin (-70^{\circ})=-112.7$

where the negative sign means the direction is along negative y:

So, vector B has the greater y component.

8 0

3 years ago

What will be the change in velocity of a 850kg car if a force of 50,000 N

yKpoI14uk [10]

Answer:

29.412m/s

Explanation:

$F=ma$ where F= force, m= mass, and a=acceleration

we also know that,

a = Δv / t where Δv = change in velocity and t = time

thus F = m ( Δv / t)

$50000=850(\frac{v}{0.5})$

$\frac{50000}{1700}=$ Δv

29.412m/s=Δv

8 0

3 years ago

What displacement in cm would occur with a 75 N/m spring if you placed a 300 N weight on the spring?

ollegr [7]

Surface tension=75N/m

Weight=300N

$\\ \bull\tt\longmapsto Surface\:Tension=\dfrac{Weight}{Displacement}$

$\\ \bull\tt\longmapsto Displacement=\dfrac{Weight}{Surface\:Tension}$

$\\ \bull\tt\longmapsto Displacement=\dfrac{300}{75}$

$\\ \bull\tt\longmapsto Displacement=4m$

$\\ \bull\tt\longmapsto Displacement=400cm$

6 0

3 years ago