All categories

3 years ago

A train moves from rest to a speed of 25 m/s in 30.0 seconds . What is the acceleration

1 answer:

7 0

When a car moves from rest then the initial velocity,
$u = 0m {s}^{ - 1}$

The final velocity,

$v = 25m {s}^{ - 1}$
and time,
$t = 30s$
Using the equation,
$v = u + at$
We have,

$25 = 0 + a(30)$
$25 = 30a$
$\frac{25}{30} = a$
$\therefore \: a = \frac{5}{6} m {s}^{ - 2}$

You might be interested in

A lightweight vertical spring of force constant k has its lower end mounted on a table. You compress the spring by a distance d,

shusha [124]

Answer:

$v=d\sqrt{\frac{k}{m}}$

Explanation:

In order to solve this problem, we can do an analysis of the energies involved in the system. Basically the addition of the initial potential energy of the spring and the kinetic energy of the mass should be the same as the addition of the final potential energy of the spring and the kinetic energy of the block. So we get the following equation:

$U_{0}+K_{0}=U_{f}+K_{f}$

In this case, since the block is moving from rest, the initial kinetic energy is zero. When the block loses contact with the spring, the final potential energy of the spring will be zero, so the equation simplifies to:

$U_{0}=K_{f}$

The initial potential energy of the spring is given by the equation:

$U_{0}=\frac{1}{2}kd^{2}$

the Kinetic energy of the block is then given by the equation:

$K_{f}=\frac{1}{2}mv_{f}^{2}$

so we can now set them both equal to each other, so we get:

$=\frac{1}{2}kd^{2}=\frac{1}{2}mv_{f}^{2}$

This new equation can be simplified if we multiplied both sides of the equation by a 2, so we get:

$kd^{2}=mv_{f}^{2}$

so now we can solve this for the final velocity, so we get:

$v=d\sqrt{\frac{k}{m}}$

6 0

3 years ago

What are the uses of rockets

lora16 [44]

They are used to be able to go out of Earth and into space to Be able to explore and toBe able to prove and tell about Earth and space

8 0

3 years ago

PLEASE HURRY 20 PTS

Crank

Answer:

A. The electric field points to the left because the force on a negative charge is opposite to the direction of the field.

Explanation:

The electric force exerted on a charge by an electric field is given by:

where

F is the force

q is the charge

E is the electric field

We see that if the charge is negative, q contains a negative sign, so the force F and the electric field E will have opposite signs (which means they have opposite directions). This is due to the fact that the direction of the lines of an electric field shows the direction of the electric force experienced by a positive charge in that electric field: therefore, a negative charge will experience a force into opposite direction.

5 0

3 years ago

How far does a car travel in 90 seconds if it’s traveling 55 m/s? Show equation

podryga [215]

You just said the car is traveling at the speed of 55 m/s. If I understand this correctly, that means the car will cover:

55 meters in the first second,

55 meters in the 2nd second,

55 meters in the 3rd second,

55 meters in the 4th second,

55 meters in the 5th second,

55 meters in the 87th second,

55 meters in the 88th second,

55 meters in the 89th second, and

55 meters in the 90th second.

That's 55 meters 90 times. If you just move these words around a little bit, it says "90 times 55 meters" . . . a pretty simple arithmetic problem.

The equation is . . . Distance = (55 m/s) times (time, in seconds) .

I get 4,953 meters. You should check me on this.

8 0

3 years ago

An electric field is produced by the very long, uniformly charged rod drawn above. If the strength of the electric field is E1 a

Debora [2.8K]

Answer: hello the complete question is attached below

answer :

r2 = 4r1

Explanation:

Electric field strength = F / q

we will assume the rod has an infinite length

For an infinitely charged rod

E ∝ 1/ r

considering two electric fields E1 and E2 at two different locations as described in the question

E1/E2 = r1/r2 ----- ( 2 )

Calculate for r2 when E2 = E1/4

back to equation 2

E1 / (E1/4) = r1 / r2

∴ r2 = 4r1

3 0

3 years ago