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Lemur [1.5K]
3 years ago
9

A toy projectile is fired from the ground vertically upward with an initial velocity of 26.5 m/s. The project arrives at its max

imum altitude in 2.7s.
What is the velocity of the projectile when it hits the ground? How?
Physics
1 answer:
elena-14-01-66 [18.8K]3 years ago
7 0
<span>26.5 m/s Ignoring air resistance, the projectile will have an initial kinetic energy expressed by E = 0.5 M V^2 and as the projectile travels upward, it's kinetic energy will decrease while it's potential gravitational kinetic energy increases such that the sum of both is constant. Then once it starts to descent, the potential energy is converted back into kinetic energy. And when it finally reaches the ground, it's kinetic energy will exactly match the original kinetic energy it had initially. And the only way it can match since the mass never changes is for it to have the same velocity as it had when it was first fired.</span>
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Why are objects that fall near earth’s surface rarely in free fall?
Sloan [31]

Answer:

Because of the presence of air resistance

Explanation:

When an object is in free fall, ideally there is only one force acting on it:

- The force of gravity, W = mg, that pushes the object downward (m= mass of the object, g = acceleration of gravity)

However, this is true only in absence of air (so, in a vacuum). When air is present, it exerts a frictional force on the object (called air resistance) with upward direction (opposite to the motion of free fall) and whose magnitude is proportional to the speed of the object.

Therefore, it turns out that as the object falls, its speed increases, and therefore the air resistance acting against it increases too; as a result, the at some point the air resistance becomes equal (in magnitude) to the force of gravity: when this happens, the net acceleration of the object becomes zero, and so the speed of the object does not increase anymore. This speed reached by the object is called terminal velocity.

3 0
3 years ago
A block is on a frictionless table, on earth. The block accelerates at 7.5 m/s when a 70 N horizontal force is applied to it. Th
Liono4ka [1.6K]

Answer:

The weight of the block on the moon is 15 kg.

Explanation:

It is given that,

The acceleration of the block, a = 7.5 m/s²

Force applied to the box, F = 70 N

The mass of the block will be, m=\dfrac{F}{a}

m=\dfrac{70\ N}{7.5\ m/s^2}

m = 9.34 kg

The block and table are set up on the moon. The acceleration due to gravity at the surface of the moon is 1.62 m/s². The mass of the object remains the same. It weight W is given by :

W=m\times g

W=9.34\ kg\times 1.62\ m/s^2

W = 15.13 N

or

W = 15 N

So, the weight of the block on the moon is 15 kg. Hence, this is the required solution.

3 0
3 years ago
At what point is the KINETIC ENERGY at its highest?
igomit [66]

Answer:

An object has the MOST kinetic energy when it's movement is the GREATEST.

Explanation:

8 0
3 years ago
FIGURE 1 shows part of a mass spectrometer. The whole arrangement is in a vacuum. Negative ions of mass 2.84 x 10-20 kg and char
yuradex [85]

Yes, the ions can exit slit P without being deflected, if the electric field strength is 170.6 N/C

Explanation:

When the ions are inside the container, they are subjected to two forces, with directions opposite to each other:

  • The force due to the electric field, whose magnitude is F_E=qE, where q is the charge of the ion and E is the strength of the electric field
  • The force due to the magnetic field, whose magnitude is F_B=qvB, where v is the speed of the ions and B is the strength of the magnetic field

The ions will move straight and undeflected if the two forces are equal and opposite. By using Fleming Left Hand rule, we notice that the magnetic force on the (negative) ions point upward: this means that the electric field must be also upward (so that the electric force on the ions is downward). Then, the two forces are balanced if

F_E = F_B

which translates into

qE=qvB\\\rightarrow v = \frac{E}{B}

Therefore, if the speed of the ions is equal to this ratio, the ions will go undeflected.

We can even calculate the value of E at which this occurs. In fact, we know that the ions are earlier accelerated by a potential difference V=-3000 V, so we have that their kinetic energy is given by the change in electric potential energy:

qV=\frac{1}{2}mv^2

where

q=-2.0\cdot 10^{-19}C\\m=2.84\cdot 10^{-20}kg

Solving for v, the speed,

v=\sqrt{\frac{2qV}{m}}=\sqrt{\frac{2(-2.0\cdot 10^{-19})(-3000)}{2.84\cdot 10^{-20}}}=205.6 m/s

And since the magnetic field strength is

B = 0.83 T

The strength of the electric field must be

E=vB=(205.6 m/s)(0.83 T)=170.6 N/C

Learn more about electric and magnetic fields:

brainly.com/question/8960054

brainly.com/question/4273177

brainly.com/question/3874443

brainly.com/question/4240735

#LearnwithBrainly

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3 years ago
(D.) Define the following Moment (.) Moment of a force (.) couple of force (.) torque<br>​
erik [133]
Moment of force. Hope this helped
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3 years ago
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