Answer:
1. 20.54m/s
2. 1.52s
Explanation:
QUESTION 1:
The speed the stone impact the ground is the final speed/velocity, which can be calculated using the formula:
v² = u² + 2as
Where;
v = final velocity (m/s)
u = initial velocity (m/s)
a = acceleration due to gravity (m/s²)
s = distance (m)
From the provided information, u = 5.65m/s, v = ?, s = 19.9m, a = 9.8m/s²
v² = 5.65² + 2 (9.8 × 19.9)
v² = 31.9225 + 2 (195.02)
v² = 31.9225 + 390.04
v² = 421.9625
v = √421.9625
v = 20.5417
v = 20.54m/s
QUESTION 2:
Using v = u + at
Where v = final velocity (m/s) = 20.54m/s
t = time (s)
u = initial velocity (m/s) = 5.65m/s
a = acceleration due to gravity (m/s²)
v = u + at
20.54 = 5.65 + 9.8t
20.54 - 5.65 = 9.8t
14.89 = 9.8t
t = 14.89/9.8
t = 1.519
t = 1.52s
1.) C
2.) B
3.) D
4.) B
Good luck with your work!
He proposed the sun-centered model of the solar system.
Answer:
377 nm
Explanation:
Number of lines per meter is, 
Grating element is, 
![=1.8868 \times 10^{-6} \mathrm{~m}[tex] Order is, n=5 Condition for maximum intensity is, [tex]d \sin \theta=n \lambda](https://tex.z-dn.net/?f=%3D1.8868%20%5Ctimes%2010%5E%7B-6%7D%20%5Cmathrm%7B~m%7D%5Btex%5D%0A%3C%2Fp%3E%3Cp%3EOrder%20is%2C%20n%3D5%0A%3C%2Fp%3E%3Cp%3ECondition%20for%20maximum%20intensity%20is%2C%20%5Btex%5Dd%20%5Csin%20%5Ctheta%3Dn%20%5Clambda)
mass of the ball m = 0.63 kg
initial height h = 1.8 m
final height h ' = 3.03 m
initial speed v = 7.09 m / s
final speed v ' = 4.21 m / s
Let the work done on the ball by air resistance W = ?
we know from law of conservation of energy ,
total energy at height h + work done by air = total energy at height h '
mgh + ( 1/ 2) mv^ 2 + W = mgh ' + ( 1/ 2) mv'^ 2
0.630*9.8*1.8 + 0.63*7.09^2 + W = mgh ' + ( 1/ 2) mv'^ 2
From there you can find W
if there is negative sign indicates it work opposite direction to motion
