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lisov135 [29]
2 years ago
5

A woman hikes 2.5 kilometers in 30 minutes, and then 3 kilometers in 20 minutes, and finally 2 kilometers in 10 minutes. What wa

s her average speed?
Physics
1 answer:
nalin [4]2 years ago
3 0

Answer:

7.5 kph

Explanation:

2.5+3+2=7.5

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When the acceleration of a mass on a spring is zero, the velocity is at a
Sergeu [11.5K]

1) Maximum

2) Maximum

Explanation:

The force acting on a mass on a spring is given by Hooke's law; in magnitude:

F=kx

where

F is the force

k is the spring constant

x is the displacement

Also we know from Newton's second law that we can write

F=ma

where

m is the mass

a is the acceleration

So we can write the equation as

ma=kx (1)

From this relationship, we see that the acceleration is directly proportional to the displacement.

On the other hand, we know that the total mechanical energy of the system mass-spring is constant, and it is given by

E=\frac{1}{2}kx^2+\frac{1}{2}mv^2=const. (2)

where the first term is the elastic potential energy while the second term is the kinetic energy, and where

v is the velocity of the mass

From eq. (2), it is clear that when displacement increases, velocity decreases, and vice-versa; however, from eq.(1) we also know that acceleration is proportional to the displacement.

Therefore this means that:

- When acceleration increases, velocity decreases

- When acceleration decreases, velocity increases

Therefore, the two answers here are:

- When the acceleration of a mass on a spring is zero, the velocity is at a  maximum

When the velocity of a mass on a spring is zero, the acceleration is at a  maximum

6 0
3 years ago
A 1000 kg rocket carrying 25 kg of fuel and oxygen rises at a velocity of 305 m/s. If all the mass of fuel and oxygen is burned
Thepotemich [5.8K]

If all the mass of fuel and oxygen is burned to form gases of combustion, the downward velocity of these gases would be 12,505 m/s.

<h3>Conservation of linear momentum</h3>

The principle of conservation of linear momentum states that, the total momentum of an isolated system is constant.

The downward velocity of thes gases is calculated as follows;

v1(m1 + m2) = v2(m2)

305(1000 + 25) = v2(25)

312,625 = 25v2

v2 = 312,625/25

v2 = 12,505 m/s

Thus, If all the mass of fuel and oxygen is burned to form gases of combustion, the downward velocity of these gases would be 12,505 m/s.

Learn more about linear momentum here: brainly.com/question/7538238

5 0
2 years ago
How long will it be before 82.0<br> % of an isotope with a half life of 1250<br> y decays?
Solnce55 [7]
Can you give more information
5 0
3 years ago
What causes some materials to have a magnetic fields?
Viktor [21]
Well it determines on how much  magnetism a material has.
6 0
3 years ago
Read 2 more answers
PLS PLS PLS PLS PLS PLS PLS PLS PLS PLS PLS HELP
7nadin3 [17]

Answer:

The poles of an electromagnet can even be reversed by reversing the flow of electricity. If a wire carrying an electric current is formed into a series of loops, the magnetic field can be concentrated within the loops. ... All of their little magnetic fields add together, creating a stronger magnetic field.

Explanation:

8 0
4 years ago
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