The strength of the force of gravity depends on

Peter was holding a Human Physiology textbook that weighs about 4lbs with his non- writing arm for one minute. His elbow remaine

Slav-nsk [51]

Answer:

a

When peter held the book for one minute the rate at which motor unites are fired increase steeply but as the duration increases the increese in the rate at which it is being fired becomes linear so the number of activated motors stay the same but are being activated at a more rapidly

b

The same motors are activated whilest he is hold the book for 2 minutes this is because for peter to hold the book in one fixed position one specific motor units need to be activated

Note changing the motor unites would change the positon of the hand

Explanation:

4 0

3 years ago

high school physics, no need detail explain, just give the answer, but you have to make sure thank you

andrey2020 [161]

Answer:

approximately 30 degrees

Explanation:

If it takes the cannonball 2 seconds to reach the maximum height, we can use the analysis of the vertical component of the velocity and the fact that the acceleration of gravity is the one acting opposite to this initial vertical component $(v_y)$ of the velocity. We know as well that at the top of the trajectory, the vertical component of the velocity is zero, and then the movement starts going down in it trajectory. So, the final velocity for the first part of the ascending movement is zero, giving us the following equation for the velocity under an accelerated movement (with acceleration of gravity "g" acting):

$v_f=v_i-a\,t\\v_f=v_y-g\,t\\0=v_y-9.8\,*\,2\\v_y=9.8\,*\,2=19.6 \frac{m}{s}$

By knowing the vertical component of the initial velocity (19.6 m/s), and the actual magnitude of the total initial velocity (40 m/s), we can calculate what angle was the initial velocity vector forming above the horizontal. We use for such the fact that the sine of the angle relates the opposite side of a right angle triangle with the hypotenuse, and solve for the angle using the arcsin function:

$sin(\theta)=\frac{opp}{hyp} \\sin(\theta)=\frac{19.6}{40}\\\theta=arcsin(\frac{19.6}{40})\\\theta=29.34^o$

which tells us that the closer answer shown is $30^o$

7 0

3 years ago

How are molecule shapes determined by electrons

il63 [147K]

Answer:

Using the VSEPR theory, the electron bond pairs and lone pairs on the center atom will help us predict the shape of a molecule. The shape of a molecule is determined by the location of the nuclei and its electrons. The electrons and the nuclei settle into positions that minimize repulsion and maximize attraction.Explanation:

3 0

3 years ago

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3) A driver in a 1000-kg car traveling at 24 m/s slams on the brakes and skids to a stop. If the coefticient of friction between

Natali5045456 [20]

Answer:

A) 37 m

Explanation:

The car is moving of uniformly accelerated motion, so the distance it covers can be calculated by using the following SUVAT equation:

$v^2 -u^2 = 2ad$ (1)

where

v = 0 m/s is the final velocity of the car

u = 24 m/s is the initial velocity

a is the acceleration

d is the length of the skid

We need to find the acceleration first. We know that the force responsible for the (de)celeration is the force of friction, so:

$F=ma=-\mu mg$

where

m = 1000 kg is the mass of the car

$\mu = 0.80$ is the coefficient of friction

a is the deceleration of the car

g = 9.8 m/s^2 is the acceleration due to gravity

The negative sign is due to the fact that the force of friction is against the motion of the car, so the sign of the acceleration will be negative because the car is slowing down. From this equation, we find:

$a=-\mu g$

And we can substitute it into eq.(1) to find d:

$v^2 -u^2 = 2(\-mu g) d\\d= \frac{v^2-u^2}{-2 \mu g}=\frac{0-(24 m/s)^2}{-2(0.80)(9.8 m/s^2)}=36.7 m \sim 37 m$

7 0

3 years ago

Which changes will decrease the electric force between two positively charged objects? Check all that apply.

zaharov [31]

Answer:

Moving them farther apart

Explanation:

The electric field between the two charges Q and q separated by a distance r is given by

$E = \frac{K\times Q\times q}{r^{2}}$

It shows that the electric field is inversely proportional to the square of the distance between two charges.

So, as the distance between two charges increases, the electric filed between the two charges decreases.

8 0

3 years ago

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