Answer:
<h2>
E = 2.8028*10⁻¹⁹ Joules</h2>
Explanation:
The minimum energy needed to eject electrons from a metal with a threshold frequency fo is expressed as E = hfo
h = planck's constant
fo = threshold frequency
Given the threshold frequency fo = 4.23×10¹⁴ s⁻¹
h = 6.626× 10⁻³⁴ m² kg / s
Substituting this value into the formula to get the energy E
E = 4.23×10¹⁴ * 6.626 × 10⁻³⁴
E = 28.028*10¹⁴⁻³⁴
E = 28.028*10⁻²⁰
E = 2.8028*10⁻¹⁹ Joules
An element would be the type of substance that only contains one kind of matter.
Answer:
its speed when its height was half that of its starting point is 25.46 m/s
Explanation:
Given;
final speed of the roller coaster, v = 36 m/s
Applying general equation of motion;
V² = U² + 2gh
where;
V is the final speed of the roller coaster
U is the initial speed of the roller coaster = 0
h is the height attained at a given velocity
36² = 0 + (2 x 9.8)h
1296 = 19.6 h
h = 1296/19.6
h = 66.1224 m
when its height was half that of its starting point, h₂ = ¹/₂ h
h₂ = ¹/₂(66.1224 m) = 33.061 m
At h = 33.061 m, V = ?
V² = U² + 2gh
V² = 0 + 2 x 9.8 x 33.061
V² = 648
V = √648
V = 25.46 m/s
Therefore, its speed when its height was half that of its starting point is 25.46 m/s
Answer:
0.0241875 m
Explanation:
= Mass of quarterback = 80 kg
= Mass of football = 0.43 kg
= Velocity of quarterback
= Velocity of football = 15 m/s
Time taken = 0.3 seconds
In this system as the linear momentum is conserved
Assuming this velocity is constant
The distance the quarterback will move in the horizontal direction is 0.0241875 m
