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4 years ago

Is the acceleration due to gravity in projectile motion always negative? please explain

1 answer:

3 0

Before you start working on any motion problem, YOU decide which direction you're going to call 'positive'. Everybody almost always calls UP positive, and the acceleration of gravity points down, so it winds up negative. But you could just as well call DOWN the positive direction. Then, the cannonball is fired with a negative vertical speed, and the acceleration of gravity eventually robs all of its negative speed, and makes it start falling in the positive direction. The whole thing is your choice.

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English schoolteacher who proposed the atomic theory model of matter

vodka [1.7K]

Answer:

Ernest Rutherford.

Explanation:

Ernest Rutherford

4 0

3 years ago

State characteristics of the images formed by pin - hole camera

Leokris [45]

Answer:

Real image

Explanation:

The picture is real, but it is reversed and tiny. An picture generated by a pinhole camera has certain features. As compared item, the image created by a pinhole camera is normally pretty small and looks reversed both on the vertically and horizontally axis.

8 0

3 years ago

A race car is one lap behind the lead race car when the lead car has 44 laps to go in a race. If the speed of the lead car is 55

masha68 [24]

Answer:

Speed of second car will be 57.17 m/sec

Explanation:

We have given lead car travels = 44 laps

1 laps = 1.34 km = 1340 m

So total distance = 1340×44 = 58960 m

Speed of lead car = 55.9 m/sec

We know that $time=\frac{distance}{speed}=\frac{58960}{55.9}=1054.74sec$

As the second car is 1 lap behind so distance traveled by second car = 45×1340 = 60300 m

So speed of second car will be $speed=\frac{distance}{time }=\frac{60300}{1054.74}=57.17m/sec$

3 0

3 years ago

Technician A says that with a properly operating air-conditioning system, the inlet to the compressor should be cold and the ou

Alborosie

Answer:

Only technician A is correct

Explanation:

Analysis of technician A's statements

The refrigeration cycle contains four major components: the compressor, condenser, expansion device, and evaporator. Refrigerant remains piped between these four components and is contained in the refrigerant loop.

The refrigerant begins as a cool vapor and heads to the first component:

1. the compressor

It forces the refrigerant through the system. In the process of being compressed the cool, gaseous refrigerant is turned to a very hot and high-pressure vapor.

Analysis of technician B's statement

The condenser’s job is to cool the refrigerant so that it turns from a gas into a liquid, or condenses. This happens when warm outdoor air is blown across the condenser coil that is filled with hot, gaseous refrigerant.

The evaporator is responsible for cooling the air going to the space by boiling (evaporating) the refrigerant flowing through it. This happens when warm air is blown across the evaporator as cold refrigerant moves through the evaporator coil. Heat transfers from the air to the refrigerant, which cools the air directly before it is vented to the space.

5 0

4 years ago

A projectile travels above level ground. The initial vertical component of its velocity is 0.90 m/s and the initial horizontal c

sladkih [1.3K]

<span>at maximum height the final velocity will be 0
using v=u+at and resolving vertically we get
v=0.6+(-9.81)t
v=0.6-9.81t
0=0.6-9.81t
9.81t=0.6
t=0.6/9.81
t=0.061 to 3sf

Now we need to resolve horizontally to find the horizontal distance
using s=ut+1/2at^2
However we now need the total time taken for the projectile travel and return to the ground. We can assume the time taken for the projectile to reach its maximum height and return to the ground is the same therefore
the total time is 2 x 0.061=0.122seconds. They'll be now horizontal acceleration in this case scenario therefore

Hence s=ut+1/2at^2
since a=0
s=ut
s=0.6 x 0.122
s=0.073m
</span>

5 0

3 years ago