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My name is Ann [436]
3 years ago
11

Galileo was the first scientist to do which of the following? A. estimate the speed of light B. propose the heliocentric theory

C. discover radioactivity D. define and measure speed E. invent the reflecting telescope
Physics
2 answers:
ad-work [718]3 years ago
5 0

the answer is a. estimate the speed of light.

stich3 [128]3 years ago
4 0
The answer to this question is a the estimate the speed of light
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B.adding carpet and fabric wall covering to absorb sound
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1 year ago
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Calculate the force exerted on the wall assuming that force is horizontal and using the data in the schematic representation of
Jlenok [28]

Answer:

1.93 x 10∧3 N

Explanation:

The picture attached shows the calculation

8 0
3 years ago
A 5.50 kg sled is initially at rest on a frictionless horizontal road. The sled is pulled a distance of 3.20 m by a force of 25.
kiruha [24]

(a) 69.3 J

The work done by the applied force is given by:

W=Fd cos \theta

where:

F = 25.0 N is the magnitude of the applied force

d = 3.20 m is the displacement of the sled

\theta=30^{\circ} is the angle between the direction of the force and the displacement of the sled

Substituting numbers into the formula, we find

W=(25.0 N)(3.20 m)(cos 30^{\circ})=69.3 J

(b) 0

The problem says that the surface is frictionless: this means that no friction is acting on the sled, therefore the energy dissipated by friction must be zero.

(c) 69.3 J

According to the work-energy theorem, the work done by the applied force is equal to the change in kinetic energy of the sled:

\Delta K = W

where

\Delta K is the change in kinetic energy

W is the work done

Since we already calculated W in part (a):

W = 69.3 J

We therefore know that the change in kinetic energy of the sled is equal to this value:

\Delta K=69.3 J

(d) 4.9 m/s

The change in kinetic energy of the sled can be rewritten as:

\Delta K=K_f - K_i = \frac{1}{2}mv^2-\frac{1}{2}mu^2 (1)

where

Kf is the final kinetic energy

Ki is the initial kinetic energy

m = 5.50 kg is the mass of the sled

u = 0 is the initial speed of the sled

v = ? is the final speed of the sled

We can calculate the variation of kinetic energy of the sled, \Delta K, after it has travelled for d=3 m. Using the work-energy theorem again, we find

\Delta K= W = Fd cos \theta =(25.0 N)(3.0 m)(cos 30^{\circ})=65.0 J

And substituting into (1) and re-arrangin the equation, we find

v=\sqrt{\frac{2 \Delta K}{m}}=\sqrt{\frac{2(65.0 J)}{5.50 kg}}=4.9 m/s

6 0
3 years ago
1. A car travels a distance of 200 m in 4 seconds. What is the velocity of the car?
dybincka [34]

Answer:

velocity = distance / time taken

= 200/4

= 50 m/s

is the correct answer

3 0
3 years ago
because lighting heats up the surrounding air slowly, it realationship to thunder is currently unknown true or false​
NeTakaya

Answer:

False

Explanation:

8 0
3 years ago
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