Answer:
Average speed, As = 2.2 [m/s]
Explanation:
To solve these types of problems we must remember that the average of the speeds is determined by dividing the distance over time.
With the first speed and the time of 6 [s] we can calculate the distance.
V = x/t
where:
x = distance [m]
V = velocity = 1.1 [m/s]
t = time = 6 [s]
x1 = V*t
X1 = 1.1*6
X1 = 6.6 [m]
Now with the second velocity and 6 [s], we can calculate the second distance.
X2 = 3.3*6
X2 = 19.8 [m]
Now we have to calculate the average speed. The total distance is x = x1 +x2
X = 19.8 + 6.6 = 26.4 [m]
and the total time is 12 [s]
Therefore:
As = 26.4/12
As = 2.2 [m/s]
All electromagnetic waves travel at the same speed in a vacuum: 3.0 x 10^5 (300,000) kilometres per second. some electromagnetic waves are part of the visible light spectrum and some do emit harmful radiation, but certainly not all. they travel fine on earth without the vacuum of space too.
Explanation:
After some time t the current does not passing through the circuit
=>so the back emf is zero
=>here the inductor opposes decay of the circuit
- Ldi/dt = Ri
di/dt = - R/Li
di/i = - R/Ldt
now we applying the integration on both sides
log i=-R/Lt+C
here t=0=>i=io
Log io=C
=>Log i=-R/L*t + Log io
logi-Log io=-R/L*t
Log[i/io]=-R/L*t
i/io=e^-Rt/L
i=ioe^-Rt/L
the option D is correct
Answer:
It's constant everywhere in its trajectory.
Explanation:
the projectile was launched with an initial velocity, the only acceleration that is affecting the projectile's velocity is gravity.
The acceleration of gravity is practically equal everywhere on earth, so during its trajectory, we have to take into consideration only the acceleration because of gravity.
This is only correct because the projectile was launched with an initial velocity and it's not accelerating from rest and then falls.
For this case we first think that the skateboard and the child are one body.
We have then:
1 = jug
2 = skateboard + boy
By conservation of the linear amount of movement:
M1V1i + M2V2i = M1V1f + M2V2f
Initial rest:
v1i = v2i = 0
0 = M1V1f + M2V2f
Substituting values
0 = (7.8) (3.2) + (M2) (- 0.65)
0 = 24.96 + M2 (-0.65)
-24.96 = (-0.65) M2
M2 = (-24.96) / (- 0.65) = 38.4 kg
Then, the child's mass is:
M2 = Mskateboard + Mb
Clearing:
Mb = M2-Mskateboard
Mb = 38.4 - 1.9
Mb = 36.5 Kg
answer:
the boy's mass is 36.5 Kg
