7.5 I think because it can not be 9 because it’s not close to 50
With the switch open, there's no current in the circuit, and therefore
no voltage drop across any of the dissipative elements (the resistor
or the battery's internal impedance). So the entire battery voltage
appears across the switch, and the voltmeter reads 12.0V .
Answer:
B) 20N.s is the correct answer
Explanation:
The formula for the impulse is given as:
Impulse = change in momentum
Impulse = mass × change in speed
Impulse = m × ΔV
Given:
initial speed = 40m/s
Final speed = -60 m/s (Since the the ball will now move in the opposite direction after hitting the bat, the speed is negative)
mass = 0.20 kg
Thus, we have
Impulse = 0.20 × (40m/s - (-60)m/s)
Impulse = 0.20 × 100 = 20 kg-m/s or 20 N.s
Answer:
58.24 Km/h.
Explanation:
From the question given above, the following data were obtained:
Distance (d) = 495 Km
Time (t) = 8 h 30 mins
Speed (S) =?
Next, we shall express 8 hours 30 mins to hours.
We'll begin by convert 30 mins to hour.
60 mins = 1 h
Therefore,
30 mins = 30 mins × 1 h/ 60 mins
30 mins = 0.5 hour.
Thus,
8 h 30 min = 8 + 0.5 = 8.5 hours
Speed is define as the distance travelled per unit time. Mathematically, it is expressed as:
Speed = Distance /time
With the above formula, we can obtain the speed as shown below:
Distance (d) = 495 Km
Time (t) = 8.5 hour
Speed (S) =?
Speed = Distance /time
Speed = 495 Km / 8.5 hour
Speed = 58.24 Km/h
Thus, the speed is 58.24 Km/h.
Answer:
P₂ = 138.88 10³ Pa
Explanation:
This is a problem of fluid mechanics, we must use the continuity and Bernoulli equation
Let's start by looking for the top speed
Q = A₁ v₁ = A₂ v₂
We will use index 1 for the lower part and index 2 for the upper part, let's look for the speed in the upper part (v2)
v₂ = A₁ / A₂ v₁
They indicate that A₂ = ½ A₁ and give the speed at the bottom (v₁ = 1.20 m/s)
v₂ = 2 1.20
v₂ = 2.40 m / s
Now let's write the Bernoulli equation
P₁ + ½ ρ v₁² + ρ g y₁ = P2 + ½ ρ v₂² + ρ g y₂
Let's clear the pressure at point 2
P₂ = P₁ + ½ ρ (v₁² - v₂²) + ρ g (y₁-y₂)
we put our reference system at the lowest point
y₁ - y₂ = -20 cm
Let's calculate
P₂ = 143 10³ + ½ 1000 (1.20² - 2.40²) + 1000 9.8 (-0.200)
P₂ = 143 103 - 2,160 103 - 1,960 103
P₂ = 138.88 10³ Pa
