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Masteriza [31]
3 years ago
11

An object starts from rest and accelerates uniformly in a straight line in the positive x direction. After 11 seconds, its speed

is 70.0 m/s. What is the average velocity of the object during the first 11 seconds?
Physics
1 answer:
vladimir1956 [14]3 years ago
4 0

Answer:

v_{avg}=35m/s

Explanation:

To calculate the average velocity we must know the distance traveled and do v_{avg}=\frac{d}{t}. The distance traveled is d=\frac{at^2}{2}, so we need to calculate the acceleration, which, since it's uniform, is a=\frac{\Delta v}{\Delta t}=\frac{v_f}{t}. Putting all together:

v_{avg}=\frac{d}{t}=\frac{at^2}{2t}=\frac{at}{2}=\frac{v_ft}{2t}=\frac{v_f}{2}=35m/s

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A boat race runs along a triangular course marked by buoys A, B, and C. The race starts with the boats headed west for 3700 mete
ale4655 [162]

Answer:

The  last two bearings are

49.50° and 104.02°

Explanation:

Applying the Law of cosine (refer to the figure attached):

we have

x² = y² + z² - 2yz × cosX

here,

x, y and z represents the lengths of sides opposite to the angels X,Y and Z.

Thus we have,

cos X=\frac{x^2-y^2-z^2}{-2yz}

or

cos X=\frac{y^2 + z^2-x^2}{2yz}

substituting the values in the equation we get,

cos X=\frac{2900^2 + 3700^2-1700^2}{2\times 2900\times 3700}

or

cos X=0.8951

or

X = 26.47°

similarly,

cos Y=\frac{1700^2 + 3700^2-2900^2}{2\times 1700\times 3700}

or

cos Y=0.649

or

Y = 49.50°

Consequently, the angel Z = 180° - 49.50 - 26.47 = 104.02°

The bearing of 2 last legs of race are angels Y and Z.

7 0
3 years ago
What does friction mean?
WARRIOR [948]
Rubbing on something
5 0
3 years ago
A 2.0 µF capacitor is charged through a 50,000 ohm resistor. How long does it take for the capacitor to reach 90% of full charge
Nesterboy [21]

Answer:

0.23 s

Explanation:

First of all, let's find the time constant of the circuit:

\tau=RC

where

R=50,000 \Omega is the resistance

C=2.0\mu F=2.0\cdot 10^{-6}F is the capacitance

Substituting,

\tau=(50,000 \Omega)(2.0\cdot 10^{-6}F)=0.1 s

The charge on a charging capacitor is given by

Q(t)=Q_0 (1-e^{-t/\tau} ) (1)

where

Q_0 is the full charge

we want to find the time t at which the capacitor reaches 90% of the full charge, so the time t at which

Q(t)=0.90 Q_0

Substituting this into eq.(1) we find

0.90 Q_0 = Q_0 (1-e^{-t/\tau})\\0.90=1-e^{-t/\tau}\\e^{-t/\tau}=1-0.90=0.10\\-\frac{t}{\tau}=ln(0.10)\\t=-\tau ln(0.10)=(0.1 s)ln(0.10)=0.23 s

4 0
3 years ago
Food deteriorated more slowly in a refrigerator because
REY [17]
Because the low temperature in the refrigerator slows the action of bacteria and fungi on food substances.
6 0
3 years ago
A ball is fired from a cannon at point 1 and follows the trajectory shown in the figure below. Air
AveGali [126]

In trajectory, acceleration vector is not the same with the velocity vector but it depends on the change in velocity. The acceleration path is perpendicular to the velocity vector path. The Correct answers are:

a.) D

b.) B

c.) C

d.) A

A Vector is a quantity that has both magnitude and direction.

Given that a  ball is fired from a cannon at point 1 and follows the trajectory shown in the figure.

a.) The vector best represents the ball's velocity at position 2 is D

b.) The vector best represents the ball's acceleration at point 2 is B

c.) Which vector best represents the ball's velocity at position 3 = C

d.) Which vector best represents the ball's acceleration at point  = A

In trajectory, acceleration vector is not the same with the velocity vector but depends on the change in velocity. The acceleration path is perpendicular to the velocity vector path.

At point 3, since the ball path is parabolic, the velocity at that point is not equal to zero but will tend to take a horizontal path.

Learn more here: brainly.com/question/25519989  

3 0
3 years ago
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