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jeyben [28]
4 years ago
13

. A projectile of mass 2 kg is fired with a speed of 20 m/s at an angle of 30° with respect to the horizontal. (a) Calculate the

initial total energy of the projectile given that the reference point of zero gravitational potential energy at the launch position. (b) Calculate the kinetic energy at the highest vertical position of the projectile. (c) Calculate the gravitational potential energy at the highest vertical position. (d) Calculate the maximum height that the projectile reaches. Compare this result by solving the same problem using your knowledge of projectile motion.
Physics
1 answer:
Aleonysh [2.5K]4 years ago
8 0

Answer:

Explanation:

a ) Initial kinetic energy

1/2 mv²

= .5 x 2 x 20 x 20

= 400 J

Total energy = P E + KE

0 + 400 = 400 J

b )

Velocity at the highest point will be equal to horizontal component of initial velocity

= 20 cos 30

= 17.32 m/s

Kinetic energy at the highest point

= ,5 x 2 x 17.32²

= 299.98 J

c )

gravitational potential energy at the highest vertical position

= initial total energy - kinetic energy at the highest point

= 400 - 299.98

= 100 J

d )

PE = mgh

h = PE / mg

= 100 / 2 x 9.8

= 5.1 m

e ) height achieved by a projectile

= u²sin²θ / 2g

= 20 x 20 x sin²30 / 2 x 9.8

= 5.1 m

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Lana71 [14]

Answer:

a_E=\dfrac{Gm}{r^2}

Explanation:

M_E = Mass of the Earth =  5.972 × 10²⁴ kg

G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²

r = Radius of Earth = 6371000 m

m = Mass of person

The force on the person will balance the gravitational force

M_Ea_E=\dfrac{GmM_E}{r^2}\\\Rightarrow a_E=\dfrac{Gm}{r^2}

The acceleration that the Earth will feel is a_E=\dfrac{Gm}{r^2}

7 0
3 years ago
a disk initially at rest rotates with constant angular acceleration through an angel of 50 rad in 5 sec find the angular speed o
lisov135 [29]

Recall the formula,

∆<em>θ</em> = <em>ω</em>₀ <em>t</em> + 1/2 <em>α</em> <em>t</em> ²

where ∆<em>θ</em> = angular displacement, <em>ω</em>₀ = initial angular speed (which is zero because the disk starts at rest), <em>α</em> = angular acceleration, and <em>t</em> = time. Solve for the acceleration with the given information:

50 rad = 1/2 <em>α</em> (5 s)²

<em>α</em> = (100 rad) / (25 s²)

<em>α</em> = 4 rad/s²

Now find the angular speed <em>ω </em>after 3 s using the formula,

<em>ω</em> = <em>ω</em>₀ + <em>α</em> <em>t</em>

<em>ω</em> = (4 rad/s²) (3 s)

<em>ω</em> = 12 rad/s

3 0
3 years ago
Amy is in-line skating. Her mass is 50 kg. She is rolling forward (north) on a flat section of road at 10 m/s. The rolling frict
Licemer1 [7]

Answer:

The right solution is "0.50 m/s²". A further explanation is provided below.

Explanation:

The given values are:

Mass,

m = 50 kg

Speed,

v = 10 m/s

Rolling friction acting backward (south),

f = 10 N

Air resistance acting backward (south),

F_T = 15 N

The total force acting will be:

⇒  F = -f-F

On substituting the given values, we get

⇒      =-10-15

⇒      =-25 \ N

Now,

⇒  a = \frac{F}{m}

On substituting the given values, we get

⇒     =\frac{-25}{50}

⇒     =-0.50 \ m/s^2

The horizontal acceleration will be "0.50 m/s²" because the (-)ve sign indicates it in south direction.

4 0
3 years ago
At a particular instant the magnitude of the momentum of a planet is 2.60 × 10^29 kg·m/s, and the force exerted on it by the sta
aleksley [76]

Answer:

F=(-4.8*10^22,0,0) N

Explanation:

<u>Given  :</u>

We are given the magnitude of the momentum of the planet and let us call this momentum (p_now) and it is given by p_now = 2.60 × 10^29 kg·m/s. Also, we are given the force exerted on the planet F = 8.5 × 10^22 N. and the angle between the planet and the star is Ф = 138°

Solution :

We are asked to find the parallel component of the force F The momentum here is not constant, where the planet moving along a curving path with varying speed where the rate change in momentum and the force may be varying in magnitude and direction. We divide the force here into two parts: a parallel force F to the momentum and a perpendicular force F' to the momentum.  

The parallel force exerted to the momentum will speed or reduce the velocity of the planet and does not change its moving line. Let us apply the direction cosines, we could obtain the parallel force as next  

F=|F|cosФp            (1)

Where the parallel force F is in the opposite direction of p as the angle between them is larger than 90°. Now we can plug our values for 0 and I F I into equation (1) to get the parallel force to the planet  

F=|F|cosФp

 =-4.8*10^22 N*p

<em>As this force is in one direction, we could get its vector as next  </em>

F=(-4.8*10^22,0,0) N

F=(0,-4.8*10^22,0) N

F=(0,0-4.8*10^22) N

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8 0
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Citrus2011 [14]

Explanation:

In brief, electrons are negative charges and protons are positive charges. An electron is considered the smallest quantity of negative charge and a proton the smallest quantity of positive charge.

Two negative charges repel. Also, two positive charges repel. A positive charge and a negative charge attract each other (all experimentally verified.)

Point Charge: An accumulation of electric charges at a point (a tiny volume in space) is called a point charge.

Note: When an atom loses an electron, the separated electron forms a negative charge, but the remaining that contains one less electron or consequently one more proton becomes a positive charge. A positive charge is not necessarily a single proton. In most cases, a positive charge is an atom that has lost one or more electron(s).

6 0
3 years ago
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