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
dalvyx [7]
3 years ago
9

A rock falls from a cliff and hits the ground at a velocity of 28m/s. How long did it take to fall?

Physics
1 answer:
liberstina [14]3 years ago
6 0

Answer:

2.8s

Explanation:

=>a = v-u/t

=> t = v - u / t

= 28-0 / 10

= 2.8 s

You might be interested in
A 2.2-kg block slides on a horizontal surface with a speed of v=0.80m/s and an
mina [271]

Answer:

μ = 0.33

Equal to 3.2 m/s²

Explanation:

Draw a free body diagram of the block.  There are three forces:

Normal force N pushing up.

Weight force mg pulling down.

Friction force Nμ pushing opposite the direction of motion.

Sum of forces in the y direction.

∑F = ma

N − mg = 0

N = mg

Sum of forces in the x direction.

∑F = ma

Nμ = ma

Substitute.

mgμ = ma

μ = a/g

μ = (3.2 m/s²) / (9.8 m/s²)

μ = 0.33

As found earlier, the acceleration is a = gμ.  Since g and μ are constant, a is also constant, so it does not change with velocity.

5 0
3 years ago
Heat is transferred at a rate of 2 kW from a hot reservoir at 800 K to a cold reservoir at 300 K. Calculate the rate at which th
vekshin1

Answer:

0.00417 kW/K or 4.17 W/K

Second law is satisfied.

Explanation:

Parameters given:

Rate of heat transfer, Q = 2kW

Temperature of hot reservoir, Th = 800K

Temperature of cold reservoir, Tc = 300K

The rate of entropy change is given as:

ΔS = Q * [(1/Tc) - (1/Th)]

ΔS = 2 * (1/300 - 1/800)

ΔS = 2 * 0.002085

ΔS = 0.00417 kW/K or 4.17 W/K

Since ΔS is greater than 0, te the second law of thermodynamics is satisfied.

6 0
3 years ago
Who else got stuck on a question and is NOT ready for test return at 2? its 1:58 AAAAAAA​
k0ka [10]
Good luckkkk hope you do well
3 0
3 years ago
Earth's rising atmospheric temperature is MOSTLY caused by unnatural
nataly862011 [7]
Greenhouse gases
What is Global Warming? Global warming is the unusually rapid increase in Earth's average surface temperature over the past century primarily due to the greenhouse gases released by people burning fossil fuels.Jun 3, 2010
4 0
3 years ago
WHATS THE ANSWER HELP
cluponka [151]

Explanation:

I believe part of the question is missing. can you please check on it?

is there a part where the mass of the object is mentioned?

6 0
3 years ago
Read 2 more answers
Other questions:
  • How much elastic potential energy is stored in a bungee cord with a spring constant of 10.0 N/m when the cord is stretched 2.00
    10·1 answer
  • if spiderman runs and jumps horizontally from the top of a 200m high building, what does he need his velocity to be to land on a
    5·1 answer
  • Which tool can be used to measure the volume of a liquid to one decimal place?
    5·2 answers
  • As temperature increases what energy decreases
    10·1 answer
  • Which is the best definition of wind?
    5·2 answers
  • What did James Madison foresee as an important element of the political system?
    11·2 answers
  • A skater of mass 40 kg is carrying a box of mass 5 kg. The skater has a speed of 5 m/s with respect to the floor and is gliding
    14·1 answer
  • The two types of glaciers are the U type which is found in the Rocky Mountains, and the L type which can be found in Switzerland
    13·1 answer
  • Which is a mixture?
    5·1 answer
  • A 100-m long transmission cable is suspended between two towers. If the mass density is 2. 01 kg/m and the tension in the cable
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!