HELP ME PLEASE *50 points*

Mike Powell holds the record for the long jump of 8.95 m, established in 1991. If he left the ground at an angle of 18.8°, what

maksim [4K]

Answer:

12 m/s

Explanation:

Projectile Motion

It's also known as 2D motion because the movement takes place in both axis x and y. The x-axis motion is at a constant speed since in absence of friction, no external force stops or accelerates the object. The y-axis motion is at variable speed, which is changed by the acceleration of gravity that makes the object to reach a maximum height and then go back to ground level.

The maximum horizontal distance reached (also called Range) is given by

$\displaystyle X_m=\frac{V_{o}^2sin2\theta}{g}$

Knowing that $\theta=18.8^o, X_m=8.95\ m$ , we solve for Vo

$\displaystyle V_o=\sqrt{\frac{gX_m}{sin2\theta}}$

$\displaystyle V_o=\sqrt{\frac{9.8\cdot 8.95}{sin(2\cdot 18.8^o)}}=12\ m/s$

Thus, the initial speed of Mike Powell was 12 m/s

7 0

3 years ago

A 0.0400-g positive charged ball with charge q = 6.40 μC is resting on a flat, frictionless horizontal surface. For a time of t

Leto [7]

Answer:

The height is 0.1014 m

Explanation:

Given that,

Mass = 0.0400 g

Charge $q= 6.40\ \mu C$

Time t = 0.0420 s

Electric field $E=7.80\times10^{2}\ N/C$

We need to calculate the electric force on the particle

Using formula of electric force

$F=qE$

Put the value into the formula

$F_{e}=6.40\times10^{-6}\times7.80\times10^{2}$

$F_{e}=0.004992= 0.499\times10^{-2}\ N$

We need to calculate the gravitational force

Using formula of force

$F=mg$

Put the value into the formula

$F_{g}=0.0400\times10^{-3}\times9.8$

$F_{g}=0.000392 = 0.392\times10^{-3}\ N$

We need to calculate the net force

$F_{net}=F_{e}-F_{g}$

$F_{net}=0.499\times10^{-2}-0.392\times10^{-3}$

$F_{net}=0.004598= 0.4598\times10^{-2}\ N$

We need to calculate the acceleration

Using newton's law

$F = ma$

$a = \dfrac{F}{m}$

$a=\dfrac{0.4598\times10^{-2}}{0.0400\times10^{-3}}$

$a =114.95\ m/s^2$

We need to calculate the height

Using equation of motion

$s = ut+\dfrac{1}{2}at^2$

$s=0+\dfrac{1}{2}\times114.95\times(0.0420)^2$

$s=0.1014\ m$

Hence, The height is 0.1014 m

3 0

3 years ago

A valid hypothesis must have test for proving what?

Novosadov [1.4K]

A valid hypothesis must have test for proving the observation and is realistic, it considers the varibales it wants to measure. And it is tested either finding significance or not in the relationship between the studied variables.

They utilize and make use of the scientific method in order to have clear basis and evidence for their investigations. Research method is always used to answer every scientific inquiry and in gaining evidential data or knowledge. The scientific method has the following process or at least undergoes the process of
1. Observation
2. Hypothesis
3. Experimentation
4. Interpretation of data
5. Evaluating the data
6. Passing and recording the data

These steps are crucial and the empirical data that these scientists obtain are very important to keep that is why research paper, thesis and dissertations exists.

7 0

3 years ago

A roller coaster starts from rest at point a and continues to point b on a frictionless track. what best describes the changes i

saw5 [17]

At first when the car is at the datum point where is no elevation, the kinetic energy increases while the potential energy is zero. As it travel the path and goes upward the kinetic enrgy decreases while the potential energy increases. When it goes down again the kinetic enrgy increases again while the potential energy decreases

3 0

3 years ago

Read 2 more answers

Question 14 (1 point)

mash [69]

(c) as the change in the dependent variable is in direct CORRELATION to the change in the independent variable.

7 0

3 years ago