Please help for 21! will mark brainliest

A ball is dropped from an upper floor, some unknown distance above your apartment. As you look out of your window, which is 1.50

Lelechka [254]

Answer:1.902 m

Explanation:

Given

height of apartment=1.5 m

It takes 0.21 sec to reach the bottom from apartment

So

$s=u_1t+\frac{gt^2}{2}$

$1.5=u_1\times 0.21+\frac{9.81\times 0.21^2}{2}$

$u_1=6.11 m/s$

i.e. if ball is dropped from top its velocity at window is 6.11 m/s

So height of upper floor above window

$v^2-u^2=2as$

where s= height of upper floor above window

here u=0

$6.11^2=2\times 9.81\times s$

$s=\frac{6.11^2}{2\times 9.81}$

s=1.902 m

5 0

3 years ago

Why does the sound of something moving away from you seem to change to lower and lower pitch

lesantik [10]

The doppler effect.
You are welcome.

3 0

3 years ago

A person jumps out a fourth-story window 14 m above a firefighter safety net. The survivor stretches the net 1.8 m before coming

Monica [59]

Answer:

The deceleration is $a = - 76.27 m/s^2$

Explanation:

From the question we are told that

The height above firefighter safety net is $H = 14 \ m$

The length by which the net is stretched is $s = 1.8 \ m$

From the law of energy conservation

$KE_T + PE_T = KE_B + PE_B$

Where $KE_T$ is the kinetic energy of the person before jumping which equal to zero(because to kinetic energy at maximum height )

and $PE_T$ is the potential energy of the before jumping which is mathematically represented at

$PE_T = mg H$

and $KE_B$ is the kinetic energy of the person just before landing on the safety net which is mathematically represented at

$KE_B = \frac{1}{2} m v^2$

and $PE_B$ is the potential energy of the person as he lands on the safety net which has a value of zero (because it is converted to kinetic energy )

So the above equation becomes

$mgH = \frac{1}{2} m v^2$

=> $v = \sqrt{2 gH }$

substituting values

$v = 16.57 m/s$

Applying the equation o motion

$v_f = v + 2 a s$

Now the final velocity is zero because the person comes to rest

So

$0 = 16.57 + 2 * a * 1.8$

$a = - \frac{16.57^2 }{2 * 1.8}$

$a = - 76.27 m/s^2$

4 0

2 years ago

The Lamborghini Huracan has an initial acceleration of 0.75g. Its mass, with a driver, is 1510 kg.

Cerrena [4.2K]

Answer:

11109.825 N

Explanation:

Given Data:

total mass =m=1510 kg

initial acceleration (a) =0.75g ( g=9.81 m/s² )

F=ma

= (1510)*( 0.75*9.81)

= 11109.825 N

4 0

3 years ago

A ball is dropped from a cliff. determine how far the ball fell after 7.5 seconds

grin007 [14]

Answer:

The ball fell 275.625 meters after 7.5 seconds

Explanation:

If an object is left on free air (no friction), it describes an accelerated motion in the vertical direction, powered exclusively by the acceleration of gravity. The formulas needed to compute the different magnitudes involved are

$V_f=gt$

$\displaystyle y=\frac{gt^2}{2}$

Where $V_f$ is the final speed of the object in free fall, assumed positive downwards, t is the time elapsed since the release and y is the vertical distance traveled by the object

The ball was dropped from a cliff. We need to calculate the vertical distance the ball went down in t=7.5 seconds. We'll use the formula

$\displaystyle y=\frac{gt^2}{2}$

$\displaystyle y=\frac{(9.8)(7.5)^2}{2}$

$Y=275.625\ m$

5 0

3 years ago