Answer:
Simple machines are useful because they reduce effort or extend the ability of people to perform tasks beyond their normal capabilities. Simple machines that are widely used include the wheel and axle, pulley, inclined plane, screw, wedge and lever.
Answer:

Explanation:
As we know that the level of intensity is given as

here we know



now the sound is travelling in all possible directions so we have



now for level of sound we have


270/70^2 = x/80^2
Cross multiply
270 (6400) = 4900x
x = 270(6400)/4900
352 and 32/49 feet
Hope this helps
Answer:
Explanation:
a) using the energy conservation equation
mgh = 0.5mv^2 + 0.5Iω^2
I(moment of inertia) (basket ball) = (2/3)mr^2
mgh = 0.5mv^2 + 0.5( 2/3mr^2) ( v^2/r^2)
gh = 1/2v^2 + 1/3v^2
gh = v^2( 5/6)
v =
putting the values we get

solving for h( height)
h = 3.704 m apprx
b) velocity of solid cylinder
mgh = 0.5mv^2 + 0.5( mr^2/2)( v^2/r^2) where ( I ofcylinder = mr^2/2)
g*h = 1/2v^2 + 1/4v^2
g*h = 3/4v^2
putting the value of h and g we get
v= = 6.957 m/s apprx
Answer:
k_2 = 7.815 * 10^-3 s^-1
Explanation:
Given:
- rate constant of reaction k_1 = 7.8 * 10^-3 s^-1 @ T_1 = 25 C
- rate constant of reaction k_2 = ? @ T_2 = 75 C
- The activation energy E_a = 33.6 KJ/mol
- Gas constant R = 8.314472 KJ / mol . K
Find:
- rate of reaction k_2 @ T_2 = 75 C
Solution:
- we will use a combined form of Arrhenius equations that relates rate constants k as function of E_a and temperatures as follows:
k_2 = k_1 * e ^ [(E_a / R) * ( 1 / T_1 - 1 / T_2 )
- Evaluate k_2 = 7.8 * 10^-3* e^[(33.6 / 8.314472)*(1/298 -1/348)
- Hence, k_2 = 7.815 * 10^-3 s^-1