1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
makvit [3.9K]
3 years ago
15

A cyclist travels at 15 m/s during a sprint finish. What is this speed in km/h

Physics
1 answer:
g100num [7]3 years ago
8 0

Answer:

54 km/hr

Explanation:

m/s to km/hr => 18/5

15 m/s to km/hr => 15 x 18/5 =>3 x 18 => 54km/hr

You might be interested in
A tortoise travels 15 meters (m) west, then another 13 centimeters (cm) west. How many meters total has she walked?
DENIUS [597]

Answer:

15.13m

Explanation:

change 15m to cm

1m=100cm

15m times 100=1500cm

add 1500+13 = 1513cm

in metres it will be 15.13m

7 0
3 years ago
If you travel 450 meters in 40 seconds, what is your average speed in meters per
Vedmedyk [2.9K]

Answer:

The answer is a 11.25m/s

8 0
3 years ago
Read 2 more answers
A solar cell generates a potential difference of 0.25 V when a 550 Ω resistor is connected across it, and a potential difference
Andre45 [30]

a) 400 \Omega

b) 0.43 V

c) 0.44 %

Explanation:

a)

For a battery with internal resistance, the relationship between emf of the battery and the terminal voltage (the voltage provided) is

V=E-Ir (1)

where

V is the terminal voltage

E is the emf of the battery

I is the current

r is the internal resistance

In this problem, we have two situations:

1) when R_1=550 \Omega, V_1=0.25 V

Using Ohm's Law, the current is:

I_1=\frac{V_1}{R_1}=\frac{0.25}{550}=4.5\cdot 10^{-4} A

2) when R_2=1000 \Omega, V_2=0.31 V

Using Ohm's Law, the current is:

I_2=\frac{V_2}{R_2}=\frac{0.31}{1000}=3.1\cdot 10^{-4} A

Now we can rewrite eq.(1) in two forms:

V_1 = E-I_1 r

V_2=E-I_2 r

And we can solve this system of equations to find r, the internal resistance. We do it by substracting eq.(2) from eq(1), we find:

V_1-V_2=r(I_2-I_1)\\r=\frac{V_1-V_2}{I_2-I_1}=\frac{0.25-0.31}{3.1\cdot 10^{-4}-4.5\cdot 10^{-4}}=400 \Omega

b)

To find the electromotive force (emf) of the solar cell, we simply use the equation used in part a)

V=E-Ir

where

V is the terminal voltage

E is the emf of the battery

I is the current

r is the internal resistance

Using the first set of data,

V=0.25 V is the voltage

I=4.5\cdot 10^{-4}A is the current

r=400\Omega is the internal resistance

Solving for E,

E=V+Ir=0.25+(4.5\cdot 10^{-4})(400)=0.43 V

c)

In this part, we are told that the area of the cell is

A=4.0 cm^2

While the intensity of incoming radiation (the energy received per unit area) is

Int.=5.5 mW/cm^2

This means that the power of the incoming radiation is:

P=Int.\cdot A=(5.5)(4.0)=22 mW = 0.022 W

This is the power in input to the resistor.

The power in output to the resistor can be found by using

P'=I^2R

where:

R=1000 \Omega is the resistance of the resistor

I=3.1\cdot 10^{-4} A is the current on the resistor (found in part A)

Susbtituting,

P'=(3.1\cdot 10^{-4})^2(1000)=9.61\cdot 10^{-5} W

Therefore, the efficiency of the cell in converting light energy to thermal energy is:

\epsilon = \frac{P'}{P}\cdot 100 = \frac{9.6\cdot 10^{-5}}{0.022}=0.0044\cdot 100 = 0.44\%

7 0
3 years ago
The initial and final velocities of two blocks experiencing constant acceleration are respectively −7.45 m/s and 14.9 m/s. (a) T
ikadub [295]

Answer:

a) a_{1}=3.7 m/s^{2}

b) a_{2}=3.68 m/s^{2}

Explanation:

a) The displacement of the first object is 22.5 m, so we can use the next equation:

v_{f}^{2}=v_{i}^{2}+2a\Delta x

a=\frac{v_{f}^{2}-v_{i}^{2}}{2x}

a=\frac{14.9^{2}-(-7.45)^{2}}{2*22.5}

a_{1}=3.7 m/s^{2}

positive acceleration.

b) Using the same equation we can find the second value of the acceleration:

a=\frac{v_{f}^{2}-v_{i}^{2}}{2x}

a=\frac{14.9^{2}-(-7.45)^{2}}{2*22.6}

a_{2}=3.68 m/s^{2}

positive acceleration.

I hope it helps you!

8 0
3 years ago
Please help I'll give brainliest!!
photoshop1234 [79]

Answer:

this may be wrong but when i looked it up it said “Seafloor Mapper”

Explanation:

4 0
3 years ago
Read 2 more answers
Other questions:
  • To view an interactive solution to a problem that is similar to this one, select Interactive Solution 7.24. A 0.0146-kg bullet i
    10·1 answer
  • An ice cube floats in a glass of water. Which of the following statements is true? Heat will flow from the water into the ice. H
    5·2 answers
  • A bumblebee buzzes past you at 3 m/s. The frequency of the hum made by its wings is 152 Hz. Assume the speed of sound to be 342
    5·2 answers
  • Describe an object that has decreasing kinetic energy
    14·2 answers
  • Can someone tell me how to find acceleration with only using distance and time? It would be much appreciated
    14·1 answer
  • If a ball is thrown straight up, where is its acceleration the<br> greatest
    15·1 answer
  • An athlete at the gym holds a 2.5 kg steel ball in his hand. His arm is 70 cm long and has a mass of 4.0 kg.
    15·1 answer
  • When an aluminum bar is connected between a hot reservoir at 720 K and a cold reservoir at 358 K, 3.00 kJ of energy is transferr
    6·1 answer
  • If the small piston has an area of .004 square
    8·1 answer
  • A 3900 kg truck is moving at 6.0 m/s what is the kinetic energy
    8·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!