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3 years ago

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6 0

) 5 -5 1 2 3 4 5 Other than at t = 0, when is the velocity of the object equal to zero? 1. 5.0 s 2. 4.0 s 3. 3.5 s 4. At no other time on this graph. correct 5. During the interval from 1.0 s to 3.0 s. Explanation: Since vt = Z t 0 a dt, vt is the area between the acceleration curve and the t axis during the time period from 0 to t. If the area is above the horizontal axis, it is positive; otherwise, it is negative. In order for the velocity to be zero at any given time t, there would have to be equal amounts of positive and negative area between 0 and t. According to the graph, this condition is never satisfied. 005 (part 1 of 1) 0 points Identify all of those graphs that represent motion at constant speed (note the axes carefully). a) t x b) t v c) t a d) t v e) t a

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What should you do if your boat capsizes answers?

nalin [4]

Many of the boating fatalities take place after capsize, but a modest list of things to do before and after a capsize can minimize boat accidents and boat accident injuries.

Initially there is an significant list of thing to do before you even step on the boat:

1. Take the boat safety and water safely courses
2. Make certain that yourself and everyone else on the boat is wearing a well-fitting and safe life jacket.
3. Go over the place of the safety items with everyone on the boat as well as the location of the horn of the boat and the flare of the boat.
4. Paint bright color the hull of the boat in order to be seen easily from the air.

After a capsize, there are significant steps to make

1. Stay calm
2. Execute a head count and check everybody for injuries or immediate dangers.
3. Ensure that everyone has floatation device that coolers and other items that can be used.
4. Stay in the capsized boat unless dangerous.
5. Try to right the boat if someone has a knowledge on how to do so.
6. Use signal devices such as flares, bright colored life jacket, whistles, flashlights and mirror.
7. Try to reboard or climb onto it in order to get as much of your body out of the cold water as possible because treading water will ground to lose body heat sooner.
8. Do not waste energy and only signal when needed. Try to keep warm and stay strong<span />

6 0

3 years ago

The car's motion can be divided into three different stages: its motion before the driver realizes he's late, its motion after t

jolli1 [7]

Answer:

B, C, D are valid assumptions

Explanation:

In each stage the acceleration of the car varies because the velocity of car varies in each stage. At first, the acceleration of the car is moving slowly.

Then, driver realizes that he is late so the acceleration of the car increases he hits the gas.

Finally, the acceleration decreases when he sees the police car.

In the first state when driver do not know, that he is late, he will drive with a constant velocity as any one does.

When the driver hits the gas and he does not know about the police vehicle, even then he may drive with constant velocity or he may accelerate the car due to fear of being caught.

In the last part of motion when driver see the police car, even than he may accelerate the car, but acceleration will be constant throughout the motion is not possible, or even than he may continue with constant velocity.

Hence, there are only three assumptions are valid.

B. During each of the three different stages of its motion, the car is moving with constant velocity.

C . The highway is straight.

D. The highway is level.

Note that the rate of change of speed is equal to the acceleration. The acceleration is constant if change in velocity of particle is equal in equal interval of time.

8 0

4 years ago

The curvature of the helix r(t)equals(a cosine t )iplus(a sine t )jplusbt k (a,bgreater than or equals0) is kappaequalsStartF

4vir4ik [10]

Answer:

$\kappa = \frac{1}{2 b}$

Explanation:

The equation for kappa ( κ) is

$\kappa = \frac{a}{a^2 + b^2}$

we can find the maximum of kappa for a given value of b using derivation.

As b is fixed, we can use kappa as a function of a

$\kappa (a) = \frac{a}{a^2 + b^2}$

Now, the conditions to find a maximum at $a_0$ are:

$\frac{d \kappa(a)}{da} \left | _{a=a_0} = 0$

$\frac{d^2\kappa(a)}{da^2} \left | _{a=a_0} < 0$

Taking the first derivative:

$\frac{d}{da} \kappa = \frac{d}{da} (\frac{a}{a^2 + b^2})$

$\frac{d}{da} \kappa = \frac{1}{a^2 + b^2} \frac{d}{da}(a)+ a * \frac{d}{da} (\frac{1}{a^2 + b^2} )$

$\frac{d}{da} \kappa = \frac{1}{a^2 + b^2} * 1 + a * (-1) (\frac{1}{(a^2 + b^2)^2} ) \frac{d}{da} (a^2+b^2)$

$\frac{d}{da} \kappa = \frac{1}{a^2 + b^2} * 1 - a (\frac{1}{(a^2 + b^2)^2} ) (2* a)$

$\frac{d}{da} \kappa = \frac{1}{a^2 + b^2} * 1 - 2 a^2 (\frac{1}{(a^2 + b^2)^2} )$

$\frac{d}{da} \kappa = \frac{a^2+b^2}{(a^2 + b^2)^2} - 2 a^2 (\frac{1}{(a^2 + b^2)^2} )$

$\frac{d}{da} \kappa = \frac{1}{(a^2 + b^2)^2} (a^2+b^2 - 2 a^2)$

$\frac{d}{da} \kappa = \frac{b^2 - a^2}{(a^2 + b^2)^2}$

This clearly will be zero when

$a^2 = b^2$

as both are greater (or equal) than zero, this implies

$a=b$

The second derivative is

$\frac{d^2}{da^2} \kappa = \frac{d}{da} (\frac{b^2 - a^2}{(a^2 + b^2)^2} )$

$\frac{d^2}{da^2} \kappa = \frac{1}{(a^2 + b^2)^2} \frac{d}{da} ( b^2 - a^2 ) + (b^2 - a^2) \frac{d}{da} ( \frac{1}{(a^2 + b^2)^2} )$

$\frac{d^2}{da^2} \kappa = \frac{1}{(a^2 + b^2)^2} ( -2 a ) + (b^2 - a^2) (-2) ( \frac{1}{(a^2 + b^2)^3} ) (2a)$

$\frac{d^2}{da^2} \kappa = \frac{-2 a}{(a^2 + b^2)^2} + (b^2 - a^2) (-2) ( \frac{1}{(a^2 + b^2)^3} ) (2a)$

We dcan skip solving the equation noting that, if a=b, then

$b^2 - a^2 = 0$

at this point, this give us only the first term

$\frac{d^2}{da^2} \kappa = \frac{- 2 a}{(a^2 + a^2)^2}$

if a is greater than zero, this means that the second derivative is negative, and the point is a minimum

the value of kappa is

$\kappa = \frac{b}{b^2 + b^2}$

$\kappa = \frac{b}{2* b^2}$

$\kappa = \frac{1}{2 b}$

3 0

3 years ago

A 10 g bullet moving horizontally with a speed of 2000 m/s strikes and passes through a 4.0 kg block moving with a speed of 4.2

Masteriza [31]

Answer:

The answer is "512 J".

Explanation:

bullet mass $m_1 = 10 g= 10^{-2} \ kg\\\\$

initial speed $u_1 = 2\ \frac{Km}{s}= 2000\ \frac{m}{s}\\\\$

block mass $m_2 = 4\ Kg$

initial speed $v_2 =-4.2 \frac{m}{s}$

final speed $v_2= 0$

Let $v_1$ will be the bullet speed after collision:

throughout the consevation the linear moemuntum

$\to M_1V_1+m_2v_2=M_1U_1+m_2u_2\\\\\to (10^{-2} kg) V_1 +0 = (10^{-2} kg)(2000 \frac{m}{s}) + (4 \ kg)(-4.2 \frac{m}{s}) \\\\\ \to 10^{-2} v_1 = 20 -16.8\\\\$

$= 320 \frac{m}{s}$

The kinetic energy of the bullet in its emerges from the block

$k=\frac{1}{2} m_1 v_1^2$

$=\frac{1}{2} \times 10^{-2} \times 320\\\\=512 \ J$

3 0

3 years ago

If the world was not tilted, what would happen to the people living on Earth

Lerok [7]

Answer:

Image result for If the world was not tilted, what would happen to the people living on Earth

If the Earth weren't tilted on its axis, there would be no seasons. And humanity would suffer. When a Mars-size object collided with Earth 4.5 billion years ago, it knocked off a chunk that would become the moon. It also tilted Earth sideways a bit, so that our planet now orbits the sun on a slant

Explanation: i looked up the answer

8 0

3 years ago

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