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kirill [66]
3 years ago
9

A car starts from rest and travels for 7.0 seconds with auniform

Physics
1 answer:
Evgen [1.6K]3 years ago
3 0

Answer

given,

initial speed = 0 m/s

acceleration of  +2.5 m/s^2 for time 7 s.

final velocity after 7 s

using equation of motion

v = u + a t

v = 0 + 2.5 x 7

v = 17.5 m/s

after 7 sec

Brake is applied, uniform acceleration = -3.0 m/s^2

time = 2 s

speed of the car after 2 s

initial velocity = 17.5 m/s

Again using equation of motion

v = u + a t

v = 17.5 - 3  x 2

v = 11.5 m/s

distance  the car has traveled when brake is applied

v² = u² + 2 a s

11.5² =17.5² - 2 x 3 x s

6 s = 174

s = 29 m

car has moved 29 m after application of the brake.

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. For transverse waves, compare the direction that the particles move to
Elza [17]

Answer:

The particles in transverse waves move perpendicular to the direction of how the wave moves.

Explanation:

5 0
3 years ago
Describe two methods that can be used to cook eggs.​
weeeeeb [17]
You can poach an egg which enfolded boiling water and stirring it and dropping a cracked egg in the water until it is fully cooked or you could hard boil and egg by boiling water and letting it cook 5,6 minutes tell you have a soft yellow center or which ever way you prefer
4 0
2 years ago
Silver has a mass of 10.5 grams and a volume of 19.3 cm3. What is its density?
Neko [114]

Answer:

<h3>The answer is 0.54 g/cm³</h3>

Explanation:

The density of a substance can be found by using the formula

density =  \frac{mass}{volume}  \\

From the question we have

density =  \frac{10.5}{19.3}  \\  = 0.54404145...

We have the final answer as

<h3>0.54 g/cm³</h3>

Hope this helps you

7 0
3 years ago
If the torque required to loosen a nut that holds a wheel on a car has a magnitude of 55 n·m, what force must be exerted at the
erastova [34]

Either 175 N or 157 N depending upon how the value of 48° was measured from.    
You didn't mention if the angle of 48° is from the lug wrench itself, or if it's from the normal to the lug wrench. So I'll solve for both cases and you'll need to select the desired answer.    
Since we need a torque of 55 N·m to loosen the nut and our lug wrench is 0.47 m long, that means that we need 55 N·m / 0.47 m = 117 N of usefully applied force in order to loosen the nut. This figure will be used for both possible angles.    
Ideally, the force will have a 0° degree difference from the normal and 100% of the force will be usefully applied. Any value greater than 0° will have the exerted force reduced by the cosine of the angle from the normal. Hence the term "cosine loss".     
If the angle of 48° is from the normal to the lug wrench, the usefully applied power will be:  
U = F*cos(48)  
where  
U = Useful force  
F = Force applied    
So solving for F and calculating gives:  
U = F*cos(48)  
U/cos(48) = F  
117 N/0.669130606 = F  
174.8537563 N = F    
So 175 Newtons of force is required in this situation.    
If the 48° is from the lug wrench itself, that means that the force is 90° - 48° = 42° from the normal. So doing the calculation again (this time from where we started plugging in values) we get  
U/cos(42) = F  
117/0.743144825 = F  
157.4390294 = F    
Or 157 Newtons is required for this case.
6 0
3 years ago
Consider the displacement vectors Ā=(i +6j)m, B = (3i– 7j)m,
andrezito [222]

Answer:

Dx = -0.5

Dy = -0.25

Explanation:

Two vectors are given in rectangular components form as follows:

A = i + 6j

B = 3i - 7j

It is also given that:

A - B - 4D = 0

so, we solve this to find D vector:

(i + 6j) - (3i - 7j) - 4D = 0

- 2i - j = 4D

D = - (2/4)i - (1/4)j

D = - (1/2)i - (1/4)j

<u>D = - 0.5i - 0.25j</u>

Therefore,

<u>Dx = -0.5</u>

<u>Dy = -0.25</u>

8 0
3 years ago
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