All categories

2 years ago

A football is kicked into the air verticaly upward. What is its(a)accelaration and(b)velocity at the highest point

Physics

1 answer:

Amiraneli [1.4K]2 years ago

8 0

Answer:

a) 9.8 m/s^2, regular earth gravity

b) 0

Explanation:

At the highest point of a ball's flight when kicked upward, it has stopped moving upward entirely and has not started moving downward yet. It therefore has no speed or velocity. However, it is still accelerating at a constant rate for the entire flight, because the earth keeps on pulling on it with the same force throughout. Hope this helps!

You might be interested in

As an electron moves, what does it make or cause ?

jolli1 [7]

It causes or makes a magnetic field.

3 0

2 years ago

Temperature and pressure of a region upstream of a shockwave are 295 K and 1.01* 109 N/m². Just downstream the shockwave, the te

seraphim [82]

Answer:

change in internal energy 3.62*10^5 J kg^{-1}

change in enthalapy 5.07*10^5 J kg^{-1}

change in entropy 382.79 J kg^{-1} K^{-1}

Explanation:

adiabatic constant $\gamma =1.4$

specific heat is given as $=\frac{\gamma R}{\gamma -1}$

gas constant =287 J⋅kg−1⋅K−1

$Cp = \frac{1.4*287}{1.4-1} = 1004.5 Jkg^{-1} k^{-1}$

specific heat at constant volume

$Cv = \frac{R}{\gamma -1} = \frac{287}{1.4-1} = 717.5 Jkg^{-1} k^{-1}$

change in internal energy $= Cv(T_2 -T_1)$

$\Delta U = 717.5 (800-295) = 3.62*10^5 J kg^{-1}$

change in enthalapy $\Delta H = Cp(T_2 -T_1)$

$\Delta H = 1004.5*(800-295) = 5.07*10^5 J kg^{-1}$

change in entropy

$\Delta S =Cp ln(\frac{T_2}{T_1}) -R*ln(\frac{P_2}{P_1})$

$\Delta S =1004.5 ln(\frac{800}{295}) -287*ln(\frac{8.74*10^5}{1.01*10^5})$

$\Delta S = 382.79 J kg^{-1} K^{-1}$

7 0

2 years ago

You are approaching a police car at 68. 1 mph and the police car is approaching you at 94. 8 mph. Assume that the speed of sound

Veronika [31]

We will hear the sound of siren of frequency 1553.4606 Hz.

<h3>What is Doppler Effect?</h3>

The apparent change in wave frequency brought on by the movement of a wave source is known as the Doppler effect. When the wave source is coming closer and when it is moving away, the perceived frequency changes. The Doppler effect explains why we hear a passing siren's sound changing in pitch.

according to Dopplers Effect,

$f'=[\frac{v + v_{0} }{v - v_{s} } ]f$