The German V-2 rocket was the first man made object in space

A passenger travels from the first floor to the 60th floor, a distance of 210 m in 35 s. what is the elevators speed

Sati [7]

Distance=210m
Time=35s

$\\ \tt\bull\leadsto Speed=\dfrac{Distance}{Time}$

$\\ \tt\bull\leadsto Speed=210/35=6m/s$

3 0

3 years ago

Read 2 more answers

A constant net force of 345 N is applied to slide a heavy stationary

liubo4ka [24]

Answer:

P = 517.5 [kg*m/s]

Explanation:

We must remember that momentum is defined as the product of force by the time of force duration.

$P=F*t$

where:

P = momentum [kg*m/s]

F = force [N]

t = time [s]

$P=345*1.5\\P=517.5[kg*m/s]$

4 0

3 years ago

An image of a car with height of 14 cm occurred in the mirror which is located at a T-

Thepotemich [5.8K]

Answer:

The distance of car form the mirror is 330 cm.

Explanation:

height of object, h = 140 cm

height of image, h' = 14 cm

radius of curvature, R = 60 cm

focal length, f = R/2 = + 30 cm

Let the distance of image is v and the distance of object is u.

$\frac{h'}{h}\frac{v}{u}\\\\\frac{14}{140} =\frac{v}{u}\\\\v =\frac{u}{10}$

Use the formula of focal length

$\frac{1}{f}=\frac{1}{v}+\frac{1}{u}\\\\\frac{1}{30}=\frac{10}{u}+\frac{1}{u}\\\\\frac{1}{30}=\frac{11}{u}\\\\u = 330 cm$

3 0

3 years ago

Find the change in thermal energy of a 25kg severed clown doll head that heats up from 25°C to 35°C, and has the specific heat o

timama [110]

Answer:

Q = 425 kJ

Explanation:

Given that,

Mass, m = 25 kg

The clown doll head that heats up from 25°C to 35°C

The specific heat is 1700 J/kg°C

We need to find the internal energy of it. The heat required to raise the temperature is given by the formula as follows :

$Q=mc\Delta T\\\\Q=25\times 1700\times (35-25)\\\\Q=425000\ J\\\\Q=425\ kJ$

So, 425 kJ of thermal energy is severed.

6 0

3 years ago

The wavelength of red helium-neon laser light in air is 632.8 nm.

e-lub [12.9K]

(a) $4.74\cdot 10^14 Hz$

The frequency of an electromagnetic wave is given by:

$f=\frac{c}{\lambda}$

where

$c=3.0\cdot 10^8 m/s$ is the speed of the wave in a vacuum (speed of light)

$\lambda$ is the wavelength

In this problem, we have laser light with wavelength

$\lambda=632.8 nm=6.33\cdot 10^{-7} m$ . Substituting into the formula, we find its frequency:

$f=\frac{3.0\cdot 10^8 m/s}{6.33\cdot 10^{-7} m}=4.74\cdot 10^14 Hz$

(b) 427.6 nm

The wavelength of an electromagnetic wave in a medium is given by:

$\lambda=\frac{\lambda_0}{n}$

where

$\lambda_0$ is the original wavelength in a vacuum (approximately equal to that in air)

$n$ is the index of refraction of the medium

In this problem, we have

$\lambda_0=632.8 nm$

n = 1.48 (index of refraction of glass)

Substituting into the formula,

$\lambda=\frac{632.8 nm}{1.48}=427.6 nm$

(c) $2.03\cdot 10^8 m/s$

The speed of an electromagnetic wave in a medium is

$v=\frac{c}{n}$

where c is the speed of light in a vacuum and n is the refractive index of the medium.

Since in this problem n=1.48, we find

$v=\frac{3\cdot 10^8 m/s}{1.48}=2.03\cdot 10^8 m/s$

3 0

4 years ago