. A car starts to move from rest. If its velocity becomes 90km/hr after 3s, calculate its acceleration

Why is your State have dimensions

Ilya [14]

Answer:

not sure you

Explanation:

8 0

3 years ago

The equation r (t )=(2t + 4)⋅i + (√ 7 )t⋅ j + 3t ²⋅k the position of a particle in space at time t. Find the angle between the v

velikii [3]

Answer:

$\theta = n\pi/2, {\rm where~n~is~an~integer.}$

Explanation:

We should first find the velocity and acceleration functions. The velocity function is the derivative of the position function with respect to time, and the acceleration function is the derivative of the velocity function with respect to time.

$\vec{v}(t) = \frac{d\vec{r}(t)}{dt} = (2)\^i + (\sqrt{7})\^j + (6t)\^k$

Similarly,

$\vec{a}(t) = \frac{d\vec{v}(t)}{dt} = (6)\^k$

Now, the angle between velocity and acceleration vectors can be found.

The angle between any two vectors can be found by scalar product of them:

$\vec{A}.\vec{B} = |\vec{A}|.|\vec{B}|.\cos(\theta)$

So,

$\vec{v}(t).\vec{a}(t) = |\vec{v}(t)|.|\vec{a}(t)|.\cos(\theta)\\36t = \sqrt{4 + 7 + 36t^2}.6.\cos(\theta)$

At time t = 0, this equation becomes

$0 = 6\sqrt{11}\cos(\theta)\\\cos(\theta) = 0\\\theta = n\pi/2, {\rm where~n~is~an~integer.}$

7 0

2 years ago

A 300 gg ball on a 70-cmcm-long string is swung in a vertical circle about a point 200 cmcm above the floor. The string suddenly

Ratling [72]

Answer:

the tension in the string an instant before it broke = 34 N

Explanation:

Given that :

mass of the ball m = 300 g = 0.300 kg

length of the string r = 70 cm = 0.7 m

At highest point, law of conservation of energy can be expressed as :

$\frac{1}{2} mv^2 = mgh\\\\v = \sqrt{2gh}\\\\v = \sqrt{2*(9.8 \ m/s^2)*(6.00 \ m - 2.00 \ m)}\\\\$

$v = 8.854 \ m/s$

The tension in the string is:

$T = \frac{mv^2}{r}\\\\T = \frac{(0.300 \ kg)*(8.854 \ m/s^2)}{0.70 \ m}\\\\T = 33.59 N\\\\T = 34 \ N$

Thus, the tension in the string an instant before it broke = 34 N

6 0

2 years ago

What does AS>0 mean?| I

tigry1 [53]

Answer:

Significant Other

Explanation:

that comes to mind when I see that

5 0

3 years ago

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Mariah trained for months leading up to the marathon, and she won. After seeing this, her friends and family would describe her

alexandr402 [8]

Answer:

Mariah trained for months leading up to the marathon and won. Her sole motivation was that after seeing her winning the marathon, her friends and family would call her as motivated and athletic. It means that Mariah wanted to fulfill her esteem needs.

Explanation:

According to Abraham Maslow:

Safety needs includes the personal security, the safety of health, resources and property. etc.

Physiological needs falls at the lowest level of basic needs. It includes food, water, rest. etc which are necessary for an individual's survival.

Esteem includes the need of respect and self-confidence.

Cognitive needs includes the desire of knowledge, to know things, to know what is happening and why is it happening around you.

In Mariah's case, she needed respect and motivation and thus she was trying to fulfill her esteem needs by winning the marathon.

8 0

3 years ago

Read 2 more answers

. A car starts to move from rest. If its velocity becomes 90km/hr after 3s, calculate its acceleration​

. A car starts to move from rest. If its velocity becomes 90km/hr after 3s, calculate its acceleration