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2 years ago

An object is dropped from a 15 m ledge. How fast it is moving just before it hits the ground?

Physics

2 answers:

loris [4]2 years ago

7 0

Answer:

$v_f = 17.15 m/s$

Explanation:

Since the ball is dropped from the height

h = 15 m

so here initial speed of the ball is

$u = 0$

acceleration of the ball due to gravity is given as

$a = 9.8 m/s^2$

now the final speed of the ball is given as

$v_f^2 - v_i^2 = 2 a d$

$v_f^2 - 0 = 2(9.8)(15)$

$v_f = 17.15 m/s$

Sergeeva-Olga [200]2 years ago

4 0

By v^2 = u^2 + 2gh
v^2 = 0 + 2 x 9.8 x 15
v = √294
v = 17.15 m/s

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The temperature, T, of a gas is jointly proportional to the pressure P of the gas and the volume V occupied by the gas. Use C as

AnnZ [28]

Answer:

T=C*P*V

Explanation:

It is said that a variable - let's call 'y' -, is proportional to another - let's call it 'x' - if x and y are multiplicatively connected to a constant 'C'. It means that their product (x*y) can be always equaled to the constant 'C' or their division ( $\frac{x}{y}$ ) can be always equaled to 'C'. The first case is the case of the inverse proportionality: It is said that x and y are inversely proportional if

$x*y=C$

The second case is the case of the direct proportionality: It is said that x and y are directly proportional if

$\frac{x}{y} =C$ : x is directly proportional to y.

$\frac{y}{x} =C$ : y is directly proportional to x.

Always that any text does not specify about directly or inversely proportionality, it is assumed to mean directly automatically.

For our case, we are said that the temperature T is proportional to the pressure P and the volume V (we assume that it means directly); it is a double proportionality but follows the same rules:

If T were just proportional to P, we would have:

$\frac{T}{P} =C$

If T were just proportional to V, we would have:

$\frac{T}{V} =C$

As T is proportional to both P and V, the right equation is:

$\frac{T}{P*V}=C$

In order to isolate the temperature, let's multiply (P*V) at each side of the equation:

$\frac{T}{P*V}*(P*V)=C*(P*V)\\T=C*P*V$

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2 years ago

A metal sphere of radius 10 cm carries a charge of +2.0 μC uniformly distributed over its surface. What is the magnitude of the

frozen [14]

Answer:

$8.0\cdot 10^5 N/C$

Explanation:

Outside the sphere's surface, the electric field has the same expression of that produced by a single point charge located at the centre of the sphere.

Therefore, the magnitude of the electric field ar r = 5.0 cm from the sphere is:

$E=k\frac{q}{(R+r)^2}$

where

$k=8.99\cdot 10^9 N m^2C^{-2}$ is the Coulomb's constant

$q=2.0 \mu C=2.0 \cdot 10^{-6}C$ is the charge on the sphere

$R=10 cm = 0.10 m$ is the radius of the sphere

$r=5.0 cm = 0.05 m$ is the distance from the surface of the sphere

Substituting, we find

$E=(8.99\cdot 10^9 Nm^2 C^{-2})\frac{2.0\cdot 10^{-6} C}{(0.10 m+0.05 m)^2}=8.0\cdot 10^5 N/C$

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2 years ago

Calculate the force a 70.0-kg high jumper must exert on the ground to produce an upward acceleration 4.00 times the acceleration

worty [1.4K]

Answer:

3433.5 N

Explanation:

g = Acceleration due to gravity = 9.81 m/s²

m = Mass of person = 70 kg

According to the question

a = Acceleration

$4g=4\times 9.81\\\Rightarrow a=39.24\ m/s^2$

Balancing the forces we have

$F-w=ma\\\Rightarrow F=ma+w\\\Rightarrow F=ma+mg\\\Rightarrow F=m(a+g)\\\Rightarrow F=70(39.24+9.81)\\\Rightarrow F=3433.5\ N$

The required force is 3433.5 N

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1 year ago

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Taya2010 [7]

Answer:

If there is any sheets or padded material in this room you can cover the window, you could turn off all the lights if there is a light switch in the room, you could try to bring a bright flashlight in and shine it into the other room(try to annoy the person watching you so they leave), act really boring and hopefully make the other person lose interest.

Explanation:

(hint) If you actually get in a situation like this place your fingernail against the mirror or glass you think could possibly be a one-way mirror. If there's a gap between your nail and the mirror, it's most likely a genuine mirror :)

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1 year ago

A coworker did not clean his work area before going home this could cause an accident so you quickly clean up the next day you s

defon

Answer:

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Explanation:

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1 year ago

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