How did you manage to overcome the difficulties that arose?

If the _____ work on a simple machine equals the output work, the machine is said to be 100% efficient.

omeli [17]

<h3>Answer:</h3>

Input work

<h3>Explanation:</h3>

Concept being tested: Efficiency of machines

Therefore we need to know what is the efficiency of a machine

Efficiency of a machine is the ratio of work output of machine to the work input expressed as a percentage.

Thus;

Efficiency = (Work output ÷ Work input) × 100%

Therefore, if the work input is equal to the work output then the efficiency of the machine will be 100%.

Most machines are not 100% efficient due to loss of energy in form of heat due to friction of the moving parts of the machine.

3 0

3 years ago

Which of the following statements is true about earth's magnetic poles

Dahasolnce [82]

Answer: b) they are the areas where Earth's magnetic field is weakest

Explanation:

According to classical physics, a magnetic field always has two associated magnetic poles (north and south), the same happens with magnets. This is because for classical physics, naturally, magnetic monopoles can not exist.

In this context, Earth is similar to a magnetic bar with a north pole and a south pole. This means, the axis that crosses the Earth from pole to pole is like a big magnet.

Now, by convention, on all magnets the north pole is where the magnetic lines of force leave the magnet and the south pole is where the magnetic lines of force enter the magnet. Then, for the case of the Earth, the north pole of the magnet is located towards the geographic south pole and the south pole of the magnet is near the geographic north pole.

Being the magnetic poles the places where the Earth's magnetic field is weakest. And it is for this reason, moreover, that the magnetic field lines enter the Earth through its magnetic south pole (which is the geographic north pole).

4 0

4 years ago

A book is dropped from a window. It takes 5 seconds to reach the ground. What is its velocity after 2 seconds? What’s the veloci

ira [324]

Answer:

Explanation:

Initial velocity is 0. In the equation v = v0+at where v0 is the initial velocity of 0, we only have to fill in -9.8 for a and 2 for t to get the velocity after 2 seconds -19.6 m/s; after 5 seconds, when it hits the ground, a = -9.8 and t = 5 to give a velocity of -49 m/s. Gravity pulls down everything at the same rate, it doesn't matter whether we drop a feather or an elephant from the window!

3 0

3 years ago

Newton’s law of universal gravitation.. . a.. is equivalent to Kepler’s first law of planetary motion.. b.. can be used to deriv

mixer [17]

By the help of newtons law of gravitation we can derive keplers third law of planetary motion.

8 0

3 years ago

Read 2 more answers

6. Jones covered a distance of 50 miles on his first trip. On a later trip he traveled 300 miles while going three times as fast

nata0808 [166]

<h3>given:</h3>

first trip= 50 miles.

second trip= 300 miles.

his new time compared to the old time.

<h3>solution:</h3>

Let speed of the 1st trip x miles / hr. and speed of the 2nd trip 3x / hr.

Speed = Distance/Time

So, times taken to covered a distance of 50 miles on his first trip = 50/x hr.

= 100/x hr

Therefore, his new time compared with the old time was twice as much.

answer= b) twice as much

5 0

2 years ago