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3 years ago

John F. Kennedy was the youngest man ever to be elected President of the United States.

Physics

1 answer:

Furkat [3]3 years ago

5 0

False. Theodore Roosevelt was the youngest.

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Cleo stated that light travels through air in straight paths, and when it moves from air to water, light changes direction, spee

Andru [333]

Answer:

Light slows down when it moves from air into water.

Explanation:

It is the property of light that travels faster in a less dense medium.

In a more dense medium, the speed of the light slows down and bends towards the normal.

The air is less dense medium and water is a more dense medium.

When light passes from air to water, the light bends.

This is known as the refraction of light.

4 0

2 years ago

Read 2 more answers

A record turntable rotates through 5.0 rad in 2.8 s as it is accelerated uniformly from rest. What is the angular velocity at th

Usimov [2.4K]

Answer:

$\omega_f = 3.584\ rad/s$

Explanation:

given,

turntable rotate to, θ = 5 rad

time, t = 2.8 s

initial angular speed = 0 rad/s

final angular speed = ?

now, using equation of rotational motion

$\theta = \omega_i t + \dfrac{1}{2}\alpha t^2$

$5 = 0+ \dfrac{1}{2}\alpha\times 2.8^2$

$\alpha= \dfrac{10}{2.8^2}$

α = 1.28 rad/s²

now, calculation of angular velocity

$\omega_f = \omega_i + \alpha t$

$\omega_f =0 +1.28\times 2.8$

$\omega_f = 3.584\ rad/s$

hence, the angular velocity at the end is equal to 3.584 rad/s

4 0

3 years ago

Which of the following calculations is equal to 1?

lutik1710 [3]

Answer:

we need to see the answers but probably 1 or -1

5 0

2 years ago

A student estimated a mass to be 325 g, but the actual mass is 342 g. What is the percent error?

Dovator [93]

Answer:

Answer:

5.2307 %

Explanation:

(acutal mass- estimated mass) / ( estimated mass)

3 0

2 years ago

A 40-kg box is being pushed along a horizontal smooth surface. The pushing force is 15 n directed at an angle of 15Â° below the

Kobotan [32]

Answer:

Acceleration of the crate is 0.362 m/s^2.

Explanation:

Given:

Mass of the box, m = 40 kg

Applied force, F = 15 N

Angle at which the force is applied, $(\theta)$ = 15°

We have to find the magnitude of the acceleration.

Let the acceleration be "a".

FBD is attached with where we can see the horizontal and vertical component of force.

⇒ $F_x=Fcos(\theta)$ and ⇒ $F_y=Fsin (\theta)$

⇒ $F_x=15cos(15)$ ⇒ $F_y=15sin (15)$

⇒ Applying concept of forces.

⇒ $\sum F_x=F_n_e_t =F-f$

⇒ $F_n_e_t =F-f$

⇒ $ma =F-f$ <em> ...Newtons second law Fnet = ma</em>

⇒ $a =\frac{F-f}{m}$

⇒ Plugging the values.

⇒ $a =\frac{15cos(15)-0}{40}$ <em>...f is the friction which is zero here.</em>

⇒ $a =\frac{14.48}{40}$

⇒ $a=0.362\ ms^-^2$

Magnitude of the acceleration of the crate is 0.362 m/s^2.

4 0

2 years ago