Answer:
5.71428571422 m/s
Explanation:
u = Initial velocity = 20 m/s
v = Final velocity
s = Displacement
a = Acceleration
Time taken = 15-1 = 14 s
Distance traveled in 1 second = 
The speed as she reaches the light at the instant it turns green is 5.71428571422 m/s
The volume of the block of wood is given by length × width ×height
= 2.75 × 4.80 × 7.5
= 99 cm³
Density is given by mass/volume
Thus = 84.0 g/ 99 cm³
= 0.848 g/cm³
Hence; since the block is less dense than water (1 g/cm³) it will float
The answer is 1.99 × 10⁻¹⁰ m.
To calculate this we will use De Broglie wavelength formula:
<span>λ = h/(m*v)
</span><span>λ - the wavelength
</span>h - Plank's constant: h = 6.626 × 10⁻³⁴ Js
v - speed
m - mass
It is given:
<span>λ = ?
</span>m = 9.11 × 10⁻²⁸<span> g
v = </span>3.66 × 10⁶<span> m/s
After replacing in the formula:
</span>λ = h/(m*v) = 6.626 × 10⁻³⁴ /(9.11 × 10⁻²⁸ * 3.66 × 10⁶) = 1.99 × 10⁻¹⁰ m
