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AfilCa [17]
2 years ago
5

A student has an 80 g sample of a radioactive material that has a half-life of 20 seconds. How much material will he have left a

fter 60 seconds?
A.
10 g

B.
20 g

C.
40 g

D.
5 g
Physics
1 answer:
Juliette [100K]2 years ago
7 0
The answer is C 40 g
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a team of dogs is pulling a sled with a net force of 2000 N. The sled is accelerating a 2.2 m/s^2. What is the mass of the sled?
sweet-ann [11.9K]
Force, F = ma

Where m = mass in kg, a = acceleration in m/s²,  Force, F is in N.

F = ma

2000 = m*2.2

2.2m = 2000

m = 2000/2.2

m ≈ 909.09

Mass is ≈ 909.09 kg.
5 0
3 years ago
A 40kg rock falls off a cliff that is 50 meters high. How fast is the speed of the rock when it hits the ground
Oksi-84 [34.3K]

31.3m/s

Explanation:

Given parameters:

Mass of rock = 40kg

Height of cliff = 50m

Unknown:

Speed of rock when it hits ground = ?

Solution:

We are going to use the appropriate motion equation to solve this problem

The rock is falling with the aid of gravitational force. The force is causing it to accelerate with an amount of velocity.

  Using;

                      V²  = U² + 2gH

V = unknown velocity

U = initial velocity = O

g = acceleration due to gravity = 9.8m/s²

H = height of fall

since the initial velocity of the bodyg is 0

     V²  = 2gH

    V= √2gH = √2 x 9.8 x 50 = 31.3m/s

learn more:

Velocity brainly.com/question/4460262

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7 0
3 years ago
a painting in an art gallery has height h and is hung so that its lower edge is a distance d above the eye of an observer. How f
harkovskaia [24]

Solution:

With reference to Fig. 1

Let 'x' be the distance from the wall

Then for \DeltaDAC:

tan\theta = \frac{d}{x}

⇒ \theta = tan^{-1} \frac{d}{x}

Now for the \DeltaBAC:

tan\theta = \frac{d + h}{x}

⇒ \theta = tan^{-1} \frac{d + h}{x}

Now, differentiating w.r.t x:

\frac{d\theta }{dx} = \frac{d}{dx}[tan^{-1} \frac{d + h}{x} -  tan^{-1} \frac{d}{x}]

For maximum angle, \frac{d\theta }{dx} = 0

Now,

0 = [/tex]\frac{d}{dx}[tan^{-1} \frac{d + h}{x} -  tan^{-1} \frac{d}{x}][/tex]

0 = \frac{-(d + h)}{(d + h)^{2} + x^{2}} -\frac{-d}{x^{2} + d^{2}}

\frac{-(d + h)}{(d + h)^{2} + x^{2}} = \frac{{d}{x^{2} + d^{2}}

After solving the above eqn, we get

x = \sqrt{\frac{d}{d + h}}

The observer should stand at a distance equal to x = \sqrt{\frac{d}{d + h}}

4 0
3 years ago
Match the correct term with each part of the wave
Misha Larkins [42]
6 . . . . . a crest
7 . . . . . the amplitude
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16. If "team A has 3 of its bocce balls closer to the pallino than any of their opponent's balls, who wins the
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Answer:

Team A wins the frame with three points. The opposing team gets zero points for the frame.

Explanation:

7 0
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