As speed (velocity) increases, potential energy increases true or false

5. A bullet is shot from a rifle with a speed of 720 m/s. What time is required for the bullet to strike a target 6400 m away?

EastWind [94]

Answer:

8.89 secs

Explanation:

720m = 1 sec

6400m = ?

6400/720 = 8.89 secs

8 0

3 years ago

What is the IMA of a two-gear system if the resistance gear has 54 teeth and the effort

Dafna1 [17]

Answer:

IMA = 2

Explanation:

Given the following data;

Resistance gear = 54 teeth

Effort gear = 23 teeth

To find the ideal mechanical advantage (IMA);

IMA = number of teeth on the resistance gear/number of teeth on the effort gear

Substituting into the equation, we have;

IMA = 54/23

IMA = 2.35 ≈ 2

Therefore, the ideal mechanical advantage (IMA) of this two-gear system is 2.

3 0

3 years ago

A sled of mass 8 kg slides along the ice. It has an initial speed of 4 m/s but

marysya [2.9K]

As our story begins, the sled ... whose mass is 8 kg ... is sliding along the ice at a speed of 4 m/s.

The sled's kinetic energy is (1/2 m v²) = (4 kg · 16 m²/s²) = 64 J .

After what seems like only the blink of an eye, the sled is no longer sliding. It is stationary. Motionless. At Rest. Just sitting there !

Its speed has been reduced to zero and ... because kinetic energy is the energy of motion ... the sled's kinetic energy is now also zero. Sixty-four Joules of energy have disappeared !

How can this be ? ! ? We know that energy is conserved. It can never just appear out of nothing, and it can never just disappear into nothing. If energy suddenly appears, it had to come from somewhere, and if energy suddenly disappears, it had to go somewhere. So where did our 64 Joules of kinetic energy go ?

It went into the ice, THAT's where ! We can say that the sled did 64J of work, and melted a thin slick layer of water on the surface of the ice. OR we can say that friction did NEGATIVE 64J of work on the sled, to cancel the 64J that it had originally, sap its kinetic energy, and bring it to rest.

I think <em>choice-B</em> was supposed to say "<em>B. -64J</em>", but somebody typed it sloppily and neglected to proofread it before posting.

6 0

3 years ago

A 500 kg dragster accelerates from rest to a final speed of 100 m/s in 400 m (about a quarter of a mile) and encounters an avera

Fantom [35]

In order to accelerate the dragster at a speed $v_f = 100 m/s$ , its engine must do a work equal to the increase in kinetic energy of the dragster. Since it starts from rest, the initial kinetic energy is zero, so the work done by the engine to accelerate the dragster to 100 m/s is
$W= K_f - K_i = K_f = \frac{1}{2}mv_f^2=2.5 \cdot 10^6 J$

however, we must take into account also the fact that there is a frictional force doing work against the dragster, and the work done by the frictional force is:
$W_f = F_f d = -(1200 N)(400 m)= -4.8 \cdot 10^5 J$
and the sign is negative because the frictional force acts against the direction of motion of the dragster.

This means that the total work done by the dragster engine is equal to the work done to accelerate the dragster plus the energy lost because of the frictional force, which is $-W_f$ :
$W_t = W + (-W_f)=2.5 \cdot 10^6 J+4.8 \cdot 10^5 J=2.98 \cdot 10^6 J$

So, the power delivered by the engine is the total work divided by the time, t=7.30 s:
$P= \frac{W}{t}= \frac{2.98 \cdot 10^6 J}{7.30 s}=4.08 \cdot 10^6 W$

And since 1 horsepower is equal to 746 W, we can rewrite the power as
$P=4.08 \cdot 10^6 W \cdot \frac{1 hp}{746 W} =547 hp$

3 0

4 years ago

Read 2 more answers

You venture out on a cold winter morning to warm up your vehicle. You have layers of cotton/polyester blend clothes on and from

xxMikexx [17]

Answer:

There is a localization of negative charge near the door handle.

4 0

3 years ago