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2 years ago

How long does it take a person to skate the width of a hockey rink (85 feet) at a constant speed of 15 feet per second?

1 answer:

3 0

S(travel distance)=85 ft
v (velocity)=15 ft/s
-----------------------------------
t (time)=?

Calculate the time with the formula for the velocity:
v=S/t
t=S/v
t=85 ft/(15 ft/s)
t=5.666s

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you walk from the park to your friend's house, then back to your house. (a) What is the distance traveled? (b) What is your disp

777dan777 [17]

Explanation:

The total distance in a path is called distance.

The shortest distance between two points is called displacement.

a) Here, the distance travelled between the park to your friend's house and back is

Distance between park to friends house + Distance from friend's house to your house.

b) Displacement would be the shortest distance between the park and your house.

a) Distance walked between your house to library and back is

Distance between your house and library + Distance between your house and library

b) Displacement would be zero (0) as the distance between you initial point and final point is zero. Here, the initial and final points are the same

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2 years ago

An expensive vacuum system can achieve a pressure as low as 1.00×10^{-7} N/m^2 at 20ºC . How many atoms are there in a cubic cen

marta [7]

Answer:

$24.70818432141\times 10^7\ atoms$

Explanation:

P = Pressure = $1\times 10^{-7}\ N/m^2$

V = Volume = 1 cm³

n = Amount of substance

N = Number of atoms

$N_A$ = Avogadro's constant = $6.022\times 10^{23}\ /mol$

R = Gas constant = 8.314 J/k mol

T = Temperature = 273.15+20 = 293.15 K

From the ideal gas law

$PV=nRT\\\Rightarrow n=\frac{PV}{RT}$

$n=\frac{N}{N_A}$

$\frac{N}{N_A}=\frac{PV}{RT}\\\Rightarrow N=N_A\times \frac{PV}{RT}\\\Rightarrow N=\frac{1\times 10^{-7}\times 1\times 10^{-6}}{8.314\times 293.15}\times 6.022\times 10^{23}\\\Rightarrow N=24708184.32141\ atoms=24.70818432141\times 10^7\ atoms$

The number of atoms is $24.70818432141\times 10^7\ atoms$

8 0

3 years ago

A 0.300 kg ball, moving with a speed of 2.5 m/s, has a head-on collision with at 0.600 kg ball initially at rest. Assuming a per

FrozenT [24]

Answer:

1.25 m/s

Explanation:

Given,

Mass of first ball=0.3 kg

Its speed before collision=2.5 m/s

Its speed after collision=2 m/s

Mass of second ball=0.6 kg

Momentum of 1st ball=mass of the ball*velocity

=0.3kg*2.5m/s

=0.75 kg m/s

Momentum of 2nd ball=mass of the ball*velocity

=0.6 kg*velocity of 2nd ball

Since the first ball undergoes head on collision with the second ball,

momentum of first ball=momentum of second ball

0.75 kg m/s=0.6 kg*velocity of 2nd ball

Velocity of 2nd ball=0.75 kg m/s ÷ 0.6 kg

=1.25 m/s

4 0

2 years ago

This property of waves is the only property where the relationship between energy and this property are indirect or inverse

yaroslaw [1]

Answer: I don't understand

Explanation:

study and pay attention

4 0

2 years ago

A capacitor with the capacitance constant C has a charge of Q and a potential difference of V.

valina [46]

the new capacitance is 2c

7 0

3 years ago