All categories

3 years ago

Is it possible to have kinetic energy and potential energy? What about neither? Give an example of each!

1 answer:

5 0

Yes they are both possible. An example of having both kinetic and gravitational potential energy could possibly be when you are travelling on a roller coaster. You are in motion and at a height. An example of neither could just be an individual sitting on a floor. They are neither in motion or at a height. Hope that helps :)

You might be interested in

Why is everything spinning? Moons, planets and stars all rotate on their axes, moons orbit planets, planets orbit stars, spiral

kow [346]

Answer:

Conservation of angular momentum

Explanation:

When the objects spread in universe after big bang, because of the tremendous force , they gained angular momentum and started to rotate. Since, then the object continue to rotate on their axis because of conservation of angular momentum. In vacuum of space there no other forces that can stop these rotation, therefore, they continue to rotate.

4 0

3 years ago

The concrete post (Ec = 3.6 × 106 psi and αc = 5.5 × 10-6/°F) is reinforced with six steel bars, each of 78-in. diameter (Es = 2

masha68 [24]

Answer:

the normal stress induced by the concrete post $\sigma_c = 67.26 psi$

the normal stress induced by the steel $\sigma_s = - 1795.84 psi$

Explanation:

Given that:

Modulus for elasticity for concrete post $E_c$ = $3.6 *10^6$ psi

Thermal coefficient for concrete post $\alpha _c$ = $5.5 *10^{-6}/^0F$

Modulus for elasticity of steel bar $E_s$ = $29*10^6psi$

Thermal coefficient of steel bar $\alpha _2$ = $6.5*10^{-6}/^0F$

Change in temperature ΔT = 80°F

Diameter of the steel rood = 7/8-in

Area of the steel rod $A_s$ = $6(\frac{ \pi}{4} )(d_s)^2$

= $6(\frac{ \pi}{4} )(\frac{7}{8} )^2$

= 3.61 in²

Area of concrete parts $A_c$ = (10)(10) - $A_s$

= (100 - 3.61) in²

= 96.39 in²

The total strain developed in the concrete post can be expressed as:

= $[\frac{1}{E_cA_c}+\frac{1}{E_sA_s}]P=(\alpha_s-\alpha_c)(\delta T)$

= $[\frac{1}{(3.6*10^6)(96.39)}+\frac{1}{(29*10^6)(3.61)}]P=(6.5*10^{-6}-5.5*10^{-6})(80)$

= $[(2.88*10^{-9}) +(9.55*10^{-9}]P = 8.0*10^{-5}$

= $1.234*10^{-8}P = 8.0*10^{-5}$

$P = \frac {8.0*10^{-5}}{1.234*10^{-8}}$

P = 6482.98 lb

Since, the normal stress in concrete is induced as a result of temperature rise; we have the expression :

$\sigma_c =\frac{P}{A_c}$

$\sigma_c = \frac{6482.98}{96.39}$

$\sigma_c = 67.26 psi$

Thus, the normal stress induced by the concrete post $\sigma_c = 67.26 psi$

Also; the normal stress in the steel bars induced as a result of temperature rise is as follows:

$\sigma_s = \frac{-P}{A_s}$

$\sigma_s =\frac{-6482.98}{3.61}$

$\sigma_s = - 1795.84 psi$

Thus, the normal stress induced by the steel $\sigma_s = - 1795.84 psi$

6 0

4 years ago

A ball is kicked at 30.0 m/s at an angle of 20.0°. Beneath the tilted columns calculate the vertical and horizontal components.

RSB [31]

The velocities at time t are

• Horizontal:

v = (30.0 m/s) cos(20.0º)

• Vertical:

v = (30.0 m/s) sin(20.0º) - g t

(where g = 9.80 m/s² is the magnitude of the acceleration due to gravity)

If you only want the initial velocities, they are

• Horizontal:

v = (30.0 m/s) cos(20.0º) ≈ 28.2 m/s

• Vertical:

v = (30.0 m/s) sin(20.0º) ≈ 10.3 m/s

(just set t = 0)

As far as starting equations go, you can derive everything from the definition for average acceleration:

a = ∆v / ∆t = (final v - initial v) / t

→ v = u + a t

(here, u stands in for "initial v" and v is simply velocity at time t )

There is no acceleration in the horizontal direction, while the ball is essentially in free-fall in the vertical direction.

6 0

3 years ago

21. An AC generator has an rms output voltage of 274 V at a frequency of 57.0 Hz.

maks197457 [2]

The answers are as follows;

a) the inductive reactance is 322 ohm

b) The maximum voltage is 387.5 V

c) The rms and maximum currents in the inductor are 1.2 A and 0.85 A.

<h3>What is the reactance?</h3>

The reactance is obtained from;

XL = 2πfL

XL = 2 * 3.14 * 57.0 * 0.900

XL = 322 ohm

The maximum voltage is obtained as;

Vo = Vrms * √2

Vo = 274 V * √2

Vo = 387.5 V

Io = Vo/XL

Io = 387.5 V/ 322 ohm

Io = 1.2 A

Irms = 274 V/322 ohm

Irms = 0.85 A

Learn more about inductive reactance:brainly.com/question/17129912

#SPJ1

4 0

2 years ago

Which set of magnets correctly illustrates the attraction of unlike poles?

ratelena [41]

Answer:

The fundamental law of magnetism states that like poles repel and unlike poles attracts each other

North and South = attraction

South and North = attraction

Explanation:

What are magnetic poles?

The magnetic poles are the two points at The end of a magnetic bar in which the magnetic properties are most pronounced.

When two opposite magnetic poles are close, they attract each other. When like poles are pushed together, there is a force of repulsion. The rule for magnets is that like poles repel and unlike poles attract.

8 0

3 years ago