Explanation:
Use the height of the cliff to determine how long it took the car to land.
Take down to be positive. Given:
Δy = 7.93 m
v₀ = 0 m/s
a = 9.8 m/s²
Find: t
Δy = v₀ t + ½ at²
7.93 m = (0 m/s) t + ½ (9.8 m/s²) t²
t = 1.27 s
Use the time to calculate the horizontal velocity.
Given:
Δx = 26.7 m
a = 0 m/s²
Find: v₀
Δx = v₀ t + ½ at²
26.7 m = v₀ (1.27 s) + ½ (0 m/s²) (1.27 s)²
v₀ = 21.0 m/s
The driver was going 21.0 m/s, faster than the speed limit of 9.72 m/s.
Answer:
Correct option : (c) period.
Explanation:
The time that is required for a vibrating object to complete one full cycle is called the time period. If f is the frequency of a wave, then the relation between the frequency and the time period is given by :
These are the characteristics of a wave. Some other characteristics are wavelength, amplitude, intensity etc. So, the correct option is (c) "period".
Answer:
Explanation:
Number of turns
N = 210turns
Length of solenoid
l = 0.18m
Cross sectional area
A = 4cm² = 4 × 10^-4m²
A. Inductance L?
Inductance can be determined using
L = N²μA/l
Where
μ is a constant of permeability of the core
μ = 4π × 10^-7 Tm/A
A is cross sectional area
l is length of coil
L is inductance
Therefore
L = N²μA / l
L=210² × 4π × 10^-7 × 4 × 10^-4 / 0.18
L = 1.23 × 10^-4 H
L = 0.123 mH
B. Self induce EMF ε?
EMF is given as
ε = -Ldi/dt
Since rate of decrease of current is 120 A/s
Then, di/dt = —120A/s, since the current is decreasing
Then,
ε = -Ldi/dt
ε = - 1.23 × 10^-4 × -120
ε = 0.01478 V
ε ≈ 0.015 V
