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andre [41]
3 years ago
6

What is an object’s acceleration if it is moving at 30 m/s and comes to a stop in 5 s? –30 m/s2 –6 m/s2 30 m/s2 6 m/s2

Physics
2 answers:
Readme [11.4K]3 years ago
7 0

Answer:

The acceleration is  -6 m/s2

Explanation:

The equation for the speed of a body is

         V = Vo + a t

Where

Vo is the initial velocity, a is the acceleration and t is the time,

When the body stops the speed is zero

       0 = Vo + a t

        a = Vo / t

substitute values

        a = - 30/5

        a = - 6 m/s2

The negative sign indicates that acceleration opposite movement

Tanya [424]3 years ago
3 0

Answer:32m/s

Explanation:

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How long would it take a leopard, running at an average speed of 20 m/s to travel 500 m?
alexandr1967 [171]

Answer:

25 seconds

Explanation:

500/20

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2 years ago
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7 0
2 years ago
A 4.80 −kg ball is dropped from a height of 15.0 m above one end of a uniform bar that pivots at its center. The bar has mass 7.
Margarita [4]

Answer:

h = 13.3 m

Explanation:

Given:-

- The mass of ball, mb = 4.80 kg

- The mass of bar, ml = 7.0 kg

- The height from which ball dropped, H = 15.0 m

- The length of bar, L = 6.0 m

- The mass at other end of bar, mo = 5.10 kg

Find:-

The dropped ball sticks to the bar after the collision.How high will the other ball go after the collision?

Solution:-

- Consider the three masses ( 2 balls and bar ) as a system. There are no extra unbalanced forces acting on this system. We can isolate the system and apply the principle of conservation of angular momentum. The axis at the center of the bar:

- The angular momentum for ball dropped before collision ( M1 ):

                                 M1 = mb*vb*(L/2)

Where, vb is the speed of the ball on impact:

- The speed of the ball at the point of collision can be determined by using the principle of conservation of energy:

                                  ΔP.E = ΔK.E

                                  mb*g*H = 0.5*mb*vb^2

                                  vb = √2*g*H

                                  vb = ( 2*9.81*15 ) ^0.5

                                  vb = 17.15517 m/s

- The angular momentum of system before collision is:

                                  M1 = ( 4.80 ) * ( 17.15517 ) * ( 6/2)

                                  M1 = 247.034448 kgm^2 /s

- After collision, the momentum is transferred to the other ball. The momentum after collision is:

                                  M2 = mo*vo*(L/2)

- From principle of conservation of angular momentum the initial and final angular momentum remains the same.

                                 M1 = M2

                                 vo = 247.03448 / (5.10*3)

                                 vo = 16.14604 m/s

- The speed of the other ball after collision is (vo), the maximum height can be determined by using the principle of conservation of energy:

                                  ΔP.E = ΔK.E

                                  mo*g*h = 0.5*mo*vo^2

                                  h = vo^2 / 2*g

                                  h = 16.14604^2 / 2*(9.81)

                                  h = 13.3 m

3 0
3 years ago
Explain how a book can have energy even if it is not moving.
frutty [35]
Can something have energy even if it's not moving?
All moving objects have kinetic energy. When an object is in motion, it changes its position by moving in a direction: up, down, forward, or backward. ... Potential energy is stored energy. Even when an object is sitting still, it has energy stored inside that can be turned into kinetic energy (motion).


Does a book at rest have energy?
A World Civilization book at rest on the top shelf of a locker possesses mechanical energy due to its vertical position above the ground (gravitational potential energy).



Does a book lying on a table have energy?
The book lying on a desk has potential energy; the book falling off a desk has kinetic energy.
5 0
2 years ago
Under certain circumstances, potassium ions (K+) in a cell will move across the cell membrane from the inside to the outside. Th
choli [55]

Answer:

1.368\times 10^{-20}\ J

Explanation:

q = Charge in the potassium ion = 19e-18e

e = Charge of electron = 1.6\times 10^{-19}\ C

V_2-V_1 = Change in potential = 0-(-85.5\times 10^{-3})

Change in electric potential is given by

E=q(V_2-V_1)\\\Rightarrow E=(19e-18e)(0-(-85.5\times 10^{-3})\\\Rightarrow E=1.6\times 10^{-19}\times 85.5\times 10^{-3}\\\Rightarrow E=1.368\times 10^{-20}\ J

The energy is 1.368\times 10^{-20}\ J

3 0
3 years ago
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