Answer:
8 seconds
Explanation:
Answer:
Explanation:
Going up
Time taken to reach maximum height= usin∅/g
=3 secs
Maximum height= H+[(usin∅)²/2g]
=80+[(60sin30)²/20]
=125 meters
Coming Down
Maximum height= ½gt²
125= ½(10)(t²)
t=5 secs
Answer:
The speed of the electron is 1.371 x 10⁶ m/s.
Explanation:
Given;
wavelength of the ultraviolet light beam, λ = 130 nm = 130 x 10⁻⁹ m
the work function of the molybdenum surface, W₀ = 4.2 eV = 6.728 x 10⁻¹⁹ J
The energy of the incident light is given by;
E = hf
where;
h is Planck's constant = 6.626 x 10⁻³⁴ J/s
f = c / λ
Photo electric effect equation is given by;
E = W₀ + K.E
Where;
K.E is the kinetic energy of the emitted electron
K.E = E - W₀
K.E = 15.291 x 10⁻¹⁹ J - 6.728 x 10⁻¹⁹ J
K.E = 8.563 x 10⁻¹⁹ J
Kinetic energy of the emitted electron is given by;
K.E = ¹/₂mv²
where;
m is mass of the electron = 9.11 x 10⁻³¹ kg
v is the speed of the electron
Therefore, the speed of the electron is 1.371 x 10⁶ m/s.
Answer:
1.) 4m
2.) 37 m
3.) 62m
4.) 2.5 s
Explanation:
1.) Given that the
Thinking distance = 1m
Breaking distance = 3m
Stopping distance = breaking distance + thinking distance
Stopping distance = 1 + 3 = 4m
2.) Given that the
Stopping distance = 52 m
Thinking distance = 15m
Breaking distance = 52 - 15 = 37m
3.) The stopping distance = 76m
Thinking distance = 14m
Breaking distance = 76 - 14 = 62m
It take the brakes 62m to slow the car down to a stop.
4.) Given that a lorry travels 28m when stopping from a speed of 4m/s. If its braking distance was 18m, what was the driver’s reaction time?
Thinking = stopping distance - braking distance
Thinking distance = 28 - 18 = 10m
Speed = distance/time
4 = 10/reaction time
Reaction time = 10/4
Reaction time = 2.5 s
5.) Question incomplete
Answer:
at rate the current change is 6.75 A / sec
Explanation:
given data
inductance L = 17 H
current I = 1.8 A
emf e = 70 V
to find out
At what rate must the current be changed
solution
we will apply here emf formula that is
emf = inductance (di/dt)
so here (di/dt) will be
di/dt = emf / inductance .......................1
put value of emf and inductance in equation 1 we get rate
di/dt = 81 / 12
di/dt = 6.75 A / sec
so at rate the current change is 6.75 A / sec
Answer:
c. 98 W
Explanation:
= initial power delivered by bulb at initial temperature = 40 W
= initial temperature of filament = 2000 K
Now the temperature of filament of the bulb rises
=Final power delivered by bulb at higher temperature
= Final higher temperature of filament = 2500 K
As per Stefan's law, the power delivered by the bulb depends directly on fourth power of the temperature. hence we can write
