Answer:
t = 2.5 hours
Explanation:
given,
speed of the bike for t time= 18 mi/h
final speed of the bike after t time = 12 mi/h
total distance, D = 69 miles
total time, T= 4.5 hour
time for which speed of the bike is 18 mi/h = ?
we know distance = speed x time
now,
18 x t + 12 (4.5 - t) = 69
6 t + 54 = 69
6 t = 15
t = 2.5 hours
The bike was at the speed of 18 mi/h for 2.5 hours.
Answer:
the current flowing in each is the same.
Explanation:
When resistors are connected in series, they are connected in the same branch of the circuit - this means that the same current flows through each resistor.
The other options listed are wrong because:
the same power is dissipated in each one --> false: the power dissipated in each resistor is
, where I is the current and R the resistance, so it depends on the value of the resistance
the potential difference across each is the same.-- > false: this is true in parallel circuits, not series circuits
the equivalent resistance of the circuit is less than that of the smallest resistor.--> false: the equivalent resistance of a series circuit is the sum of the individual resistances:
, so it is larger than the resistance of the smallest resistance
the equivalent resistance of the circuit is equal to the average of all the resistances. --> false: the equivalent resistance of a series circuit is the sum of the individual resistances:
, not the average
Answer:
1178 nm
Explanation:
We are given that
Wavelength of light=

We have to find the thickness of spacer if five dark fringes are observed between the edges of the glass.
Suppose that first dark fringe and fifth dark fringe near spacer, then the path length of light is 4 times the wavelength of light.
The light passes through air film is two times then the change in air film thickness from one edge to other is two times the wavelength of light.
Change in air film thickness from one edge to other edge is same as the thickness of spacer.
Therefore, thickness of spacer=
Thickness of spacer=
m
Thickness of spacer=1178 nm
Hence, the thickness of spacer=1178 nm
Answer:
6.1 km
Explanation:
Given that a plane travels 4.0 km at an angle of 25◦ to the ground, then changes direction and travels 10 km at an angle of 16◦ to the ground. What is the magnitude of the plane's total displacement? Answer in units of km
The magnitude of the total displacement D can be calculated by using cosine formula
Ø = 25 - 16 = 9 degree
D^2 = 4^2 + 10^2 - 2 × 4 × 10 × cos 9
D^2 = 16 + 100 - 80cos9
D^2 = 116 - 79.02
D = sqrt( 36.98)
D = 6.1 m
Therefore, the magnitude of the plane's total displacement is 6.1 km
Answer:
v = 282.84 m / s
Explanation:
The speed of a wave in a wire is given by the equation
.v = √ T /ρ
Where v is the speed of the wave, T the tension in the wire and ρ the density of the wire
If the tension is doubled
T = 2T₀
v = √ (2T₀ / ρ)
v = √2 √ T₀ / ρ
v = √2 v₀
calculate
v = √2 200
v = 282.84 m / s