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-Dominant- [34]

3 years ago

7

Alaina is pregnant and has undergone prenatal testing. The initial tests raised some red flags, and a subsequent DNA test confir

med that the fetus does in fact have three copies of chromosome 21, or:
Down syndrome.

1 answer:

vova2212 [387]3 years ago

3 0

Answer:zsg

Explanation:gzdbzd

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A ball rolls over the edge of a platform with only a horizontal velocity. The height of the platform is 1.60m and the horizontal

AysviL [449]

Answer:

v = 46.99 m/s

Explanation:

The velocity of the ball just before it touches the ground, is given by the following formula:

$v=\sqrt{v_x^2+v_y^2}$ (1)

vx: horizontal component of the velocity

vy: vertical component of the velocity

The vertical component vy is calculated by using the following formula:

$v_y^2=v_{oy}^2+2gh$ (2)

vy: final velocity

voy: initial vertilal velocity = 0m/s (because it is a semi parabolic motion)

g: gravitational acceleration = 9.8 m/s^2

h: height = 1.60m

You replace the values of the parameters in the equation (2):

$v_y=2(9.8m/s^2)(1.60m)=31.36\frac{m}{s}$

vx is calculated by using the information about the horizontal range of the ball:

$R=v_o\sqrt{\frac{2h}{g}}$ (3)

R: horizontal range of the ball = 20.0 m

You solve the previous equation for vo, the initial horizontal velocity:

$v_o=R\sqrt{\frac{g}{2h}}=(20.0m)\sqrt{\frac{9.8m/s^2}{2(1.60m)}}\\\\v_o=35\frac{m}{s}$

The horizontal component of the velocity is constant in the complete trajectory, hence, you have that

vx = vo = 35 m/s

Finally, you replace the values of vx and vy in the equation (1):

$v=\sqrt{(35m/s)^2+(31.36m/s)^2}=46.99\frac{m}{s}$

The velocity of the ball just before it touches the ground is 46.99 m/s

5 0

4 years ago

A block sliding across a level surface has a mass of 2.5 kg and a mechanical energy of 20 joules. What is its velocity?

tia_tia [17]

Hi!

The energy of the block is 4 m/s

To calculate this, you need to use the equation for kinetic energy. The block is sliding (i.e. it's moving). If the object is sliding across a level surface, the only energy it has is kinetic energy, because there is no change in potential energy (which changes with height). So, the mechanical energy will be pure kinetic energy. The equation is the following, derived from the expression for kinetic energy:

$v= \sqrt{ \frac{2*Ke}{m}}=\sqrt{ \frac{2*20 (kg*m^{2}*s^{-2}) }{2,5kg}}=4 m/s$

Have a nice day!

8 0

3 years ago

Why in example multiplying the length by 2

dolphi86 [110]

What??????? idk!!!!!

3 0

3 years ago

There are both enviromental and food stimuli that can disrupt sleep true or false

konstantin123 [22]

The answer is true. I hope that this helps you out!!

4 0

3 years ago

The escape speed from the moon is much smaller than from earth. True or False

Lisa [10]

Answer:

True

The escape speed from the Moon is much smaller than from Earth.

Explanation:

The escape speed is defined as:

$v_{e} = \sqrt{\frac{2GM}{r}}$ (1)

Where G is the gravitational constant, M is the mass and r is the radius.

The mass of the Earth is $5.972x10^{24}kg$ and its radius is $6371000m$

Then, replacing those values in equation 1 it is gotten.

$v_{e} = \sqrt{\frac{(2)(6.67x10^{-11}N.m^{2}/kg^{2})(5.972x10^{24}kg)}{(6371000m)}}$

$v_{e} = 11.18m/s$

For the case of the Moon:

$v_{e} = \sqrt{\frac{(2)(6.67x10^{-11}N.m^{2}/kg^{2})(7.347x10^{22}Kg)}{(1737000m)}}$

$v_{e} = 2.38m/s$

Hence, the escape speed from the Moon is much smaller than from Earth.

Since it has a smaller mass and smaller radius compared to that from the Earth.

4 0

3 years ago