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Yuri [45]
3 years ago
11

Two ice skaters are initially at rest. They push off and move in opposite directions. Ice Skater 1 has a mass of 90 kg and a vel

ocity of -10 meters per second. Ice Skater 2 has a mass of 105 kg. What is his velocity?
Physics
1 answer:
makvit [3.9K]3 years ago
4 0

Answer:

vB = 8.57[m/s]

Explanation:

Since there is no external force that generates momentum, the amount of momentum is conserved so you will have the following equation

m_{A}*v_{A}=m_{B}*v_{B}\\Where:\\m_{A}= 90[kg]\\v_{A}=10[m/s]\\m_{B}=105[kg]\\\\Therefore:\\\\v_{B}=\frac{m_{A}*v_{A}}{m_{B}}\\ v_{B}=\frac{90*10}{105}\\v_{B}=8.57[m/s]

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3. A 40-gram ball of clay is dropped from a height, h, above a cup which is attached to a spring of spring force constant, k, of
zheka24 [161]

Answer:

the maximum speed of the ball is 12.65 m/s

Explanation:

Given;

mass of the ball, m = 40 g = 0.04 kg

spring constant, k = 25 N/m

Apply the principle of conservation of energy;

The Elastic potential energy of the spring will be converted into Kinetic of the ball;

\frac{1}{2} kx^2 = \frac{1}{2} mv^2\\\\ kx^2 = mv^2\\\\v^2 = \frac{kx^2}{m} \\\\v = \sqrt{\frac{kx^2}{m}} \\\\v = \sqrt{\frac{(25)(0.506)^2}{0.04}} \\\\v = \sqrt{160.0225} \\\\v = 12.65 \ m/s

Therefore, the maximum speed of the ball is 12.65 m/s

4 0
2 years ago
A 500 pF capacitor is charged up so that it has 10μC of charge on its plates. The capacitor is then quicklyconnected to a 10 H i
klio [65]

Answer:

Explanation:

Given that,

A capacitor of capacitance

C = 500pF

Charge on capacitor is

Q = 10μC

Capacitor is then connected to an inductor of inductance 10H

L = 10H

Since we want to calculate the maximum energy stored by the inductor, then, we will assume all the energy from the capacitor is transfer to the inductor

So energy stored in capacitor can be determined by using

U = ½CV²

Then, Q = CV

Therefore V = Q/C

U = ½ C • (Q/C)² = ½ C × Q²/C²

U = ½Q² / C

Then,

U = ½ × (10 × 10^-6)² / (500 × 10^-9)

U = 1 × 10^-4 J

U = 0.1 mJ

So the energy stored in this capacitor is transfers to the inductor.

So, energy stored in the inductor is 0.1mJ

B. Current through the inductor

Energy in the inductor is given as

U = ½Li²

1 × 10^-4 = ½ × 10 × i²

1 × 10^-4 = 5× i²

i² = 1 × 10^-4 / 5

i² = 2 × 10^-5

I = √(2×10^-5)

I = 4.47 × 10^-3 Amps

Then,

I = 4.47 mA

8 0
3 years ago
The __________ is the part of the brain thought to be responsible for a person's hunger drive.
belka [17]
 Lateral hypothalamus tells you your hungry and the <span>Ventromedial Nuclei gives a signal to tell you to stop eating</span>
8 0
3 years ago
Read 2 more answers
1. Alexandra and Rachel are on a train that sounds a whistle at a constant frequency as
exis [7]

Answer: the answer would be C trust me i took the test if its not that its b

hope that helps

Explanation: i took the test

6 0
3 years ago
Read 2 more answers
The following table lists the work functions of a few commonmetals, measured in electron volts.
steposvetlana [31]

Answer:

Lithium

Explanation:

The equation for the photoelectric effect is

\frac{hc}{\lambda}= \phi + K_{max}

where

\frac{hc}{\lambda} is the energy of the incident photon, with

h being the Planck constant

c is the speed of light

\lambda is the wavelength of the photon

\phi is the work function of the metal (the minimum energy needed to extract the photoelectron from the metal)

K_{max} is the maximum kinetic energy of the emitted photoelectrons

In this problem, we have

\lambda= 190 nm = 1.9\cdot 10^{-7}m is the wavelength of the incident photon

K_{max}=4.0 eV is the maximum kinetic energy of the electrons

First of all we can find the energy of the incident photon

E=\frac{(6.63\cdot 10^{-34} Js)(3\cdot 10^8 m/s)}{1.90\cdot 10^{-7} m}=1.05\cdot 10^{-18} J

Converting into electronvolts,

E=\frac{1.05\cdot 10^{-18} J}{1.6\cdot 10^{-19} J/eV}=6.6 eV

So now we can re-arrange the equation of the photoelectric effect to find the work function of the metal

\phi = E-K_{max}=6.6 eV - 4.0 eV=2.6 eV

So the metal is most likely Lithium, which has a work function of 2.5 eV.

3 0
3 years ago
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