Find the value of 02?

The position of a ball rolling in a straight line is given by x=2−3.6t+4.4t2, where x is in meters and t in seconds.

kobusy [5.1K]

I'm assuming the question is time it will take for ball to reach ground, if it is then set equation to zero then use the quadratic formula, the possible t value is your answer then

8 0

3 years ago

Which of the following values has the greatest number of significant figures? Justify your answer?

Bumek [7]

The highest value with greatest significant figures is 0.0004200 grams.

Answer: Option A

Explanation:

Significant numbers are values, often measurements that contribute to the accuracy of the value. We'll start by calculating significant numbers with the first digit without zero. Calculate the number of significant digit from a series of numbers.

These have several rules to be followed for the calculation of number of significant figure at a given value. Following lead with zeros are not significant rules, we have, for option A, number of significant figure number values as 4. And, option D, we have the significant figure number value as 3. While for option B, significant figure all non-zero digits so as 3.

For option C, we have significant figure as 2 as rule is if the digit ends "0" and no decimal point, then all zeros between the position where decimal point is and non-zero numbers are not significant. Thereby, the greatest significant figure value be the option A following the rule of trailing zeros.

7 0

4 years ago

a plane is flying 120 m above the ground at an angle of 30 degrees to the horizontal, when the pilot released 2 fuel tanks to de

charle [14.2K]

Answer:

2.26 seconds

97m/s

Explanation:

1. Fall time

i) Find the vertical speed of the plane when the tanks were released

$V_{y,0}=84m/s\times sin(30\º)=42m/s$

That is the same initial vertical speed of the tanks.

ii) Find the fall time

$y-y_0=V_{y,0}\cdot t+g\cdot t^2/2$

$120=42t+4.9t^2$

$4.9t^2+42t-120=0$

$t=\dfrac{-42\pm\sqrt{(42)^2-4(4.9)(-120)}}{2\times 4.9}$

Only the positive value has aphysical meaning: t = 2.26 seconds.

2. Speed when they hit the ground

i) The horizontal speed is constant:

$V_x=84m/s\times cos(30\º)\approx72.5m/s$

ii) The vertical speed is:

$V_y=V_{y,0}+g\cdot t$

$V_y=42m/s+9.8m/s^2\cdot (2.26s)\approx64.1m/s$

iii) Total speed

$V=\sqrt{V_x^2+V_y^2}$

$V=\sqrt{(72.5m/s)^2+(64.1m/s)^2}\approx97m/s$

6 0

4 years ago

Which of the following statements is true for ideal gases, but is not always true for real gases?

xxMikexx [17]

Answer:

C. Replacing one gas by another under the same conditions, has no effect on pressure.

Explanation:

Ideal gas:

A gas is treated as an ideal gas if temperature is high and pressure is low.

Kinetic energy for ideal gas given as

$K.E.=\dfrac{3}{2}KT$

So when temperature of gas is increases then Average molecular kinetic energy will also increases.

The size of molecule is negligible as compare to the dimension of container. It mean that volume occupied by molecule is less as compare to the volume of container.

The between molecules is perfectly elastic.

Ideal gas equation

P V = m R T

So the option C is not always true.

4 0

3 years ago

Help please and thank you

nata0808 [166]

Answer:

creo que es la opcion numero 4.

8 0

2 years ago