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3 years ago

A train travels at 50 km in three hours in the 96 km in four hours what is its average speed?

Physics

1 answer:

Mariana [72]3 years ago

3 0

Answer:

≈20.9 km/hr

Explanation:

Average speed is the distance divided by time.

The train travels 50 km in 3 hours, then 96 km in 4 hours. So overall, the train travels 146 km in 7 hours. The average speed is:

146 km / 7 hr ≈ 20.9 km/hr

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PLEASE HELPPP<br> answer choices are insulator and conductor

Sergeeva-Olga [200]

Conductor is the answer

6 0

3 years ago

Doug rubs a piece of fur on a hard rubber rod, giving the rod a negative charge. Which of the following statements best describe

Leto [7]

Answer:

B is correct. Electrons are added to the rod.

Explanation:

Because the fur lose electrons to the rode and because positively charged while the rod because negative

7 0

3 years ago

A diver leaves the end of a 4.0 m high diving board and strikes the water 1.3s later, 3.0m beyond the end of the board. Consider

shutvik [7]

Answer:

4.0 m/s

Explanation:

The motion of the diver is the motion of a projectile: so we need to find the horizontal and the vertical component of the initial velocity.

Let's consider the horizontal motion first. This motion occurs with constant speed, so the distance covered in a time t is

$d=v_x t$

where here we have

d = 3.0 m is the horizontal distance covered

vx is the horizontal velocity

t = 1.3 s is the duration of the fall

Solving for vx,

$v_x = \frac{d}{t}=\frac{3.0 m}{1.3 s}=2.3 m/s$

Now let's consider the vertical motion: this is an accelerated motion with constant acceleration g=9.8 m/s^2 towards the ground. The vertical position at time t is given by

$y(t) = h + v_y t - \frac{1}{2}gt^2$

where

h = 4.0 m is the initial height

vy is the initial vertical velocity

We know that at t = 1.3 s, the vertical position is zero: y = 0. Substituting these numbers, we can find vy

$0=h+v_y t - \frac{1}{2}gt^2\\v_y = \frac{0.5gt^2-h}{t}=\frac{0.5(9.8 m/s^2)(1.3 s)^2-4.0 m}{1.3 s}=3.3 m/s$

So now we can find the magnitude of the initial velocity:

$v=\sqrt{v_x^2+v_y^2}=\sqrt{(2.3 m/s)^2+(3.3 m/s)^2}=4.0 m/s$

4 0

4 years ago

If everything that is created has to have an end, what could cause the end of the universe itself?

bearhunter [10]

Answer:

The Big Crunch hypothesis is a symmetric view of the ultimate fate of the universe. Just as the Big Bang started as a cosmological expansion, this theory assumes that the average density of the universe will be enough to stop its expansion and begin contracting.

Explanation:

hope it helps

5 0

3 years ago

Which of the following items can enter and exit an isolated system?

Mkey [24]

Neither energy nor matter can enter and exit an isolated system.

Explanation:

There are three types of systems which refers to universe. They are

1. Open System : In an open system, both energy and matter have external interactions. Example:- boiling water in an open pan.

2. Closed system : In a closed system, only energy has interaction with surroundings. Example:- boiling water with a lid on the pan.

3. Isolated system : In an isolated system, neither energy-nor matter has external interactions with surroundings. Example : a thermos flask does not exchange energy and matter.

Hence, the correct option is (a) " neither energy nor matter ".

7 0

4 years ago