Only ' A ' is always true.<em> (choice-1)</em>
' B ' is not true when you drop a red hot spoon into cold soup.
' C ' is not true when you drop a red hot marble into a cool swimming pool.
Given that a ball is thrown into the air and its height in feet after t seconds is given by y = 45t - 15t², the instantaneous velocity when t=4 is -75ft/s.
<h3>What is the instantaneous velocity when t=4?</h3>
Given that;
- Initial velocity = 45ft/s
- Height in feet after t seconds is given by y = 45t - 15t²
- Instantaneous velocity = ?
First, we determine the derivative of y = 45t - 15t²
y' = (1)45 - (2)15t
y' = 45 - 30t
We substitute in t = 4
y' = 45 - 30t
y' = 45 - 30(4)
y' = 45 - 120
y' = -75ft/s
Given that a ball is thrown into the air and its height in feet after t seconds is given by y = 45t - 15t², the instantaneous velocity when t=4 is -75ft/s.
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Answer:
3.26 secs
Explanation:
Diameter of sphere ( D )= 10 mm
T1 = 75°C
P = 1 atm
T∞ = 23°C
T2 = 35°c
Velocity = 10 m/s
<u>Determine how long it will take to cool the sphere to 35°C</u>
<em>Using the properties of copper and air given in the question</em>
Nu = 2 + (Re)^0.8 (Pr)^0.33
hd / k = 2 + ( vd/v )^0.8 (Pr)^0.33
∴ h ≈ 2594.7 W/m^2k
Given that :
(T2 - T∞) / ( T1 - T∞ ) = exp [ ( -hA / pv CP ) t ]
( 35 - 23 ) / ( 75 - 23 ) = exp [ - 2594.7 * 6 * t / 8933 * 387 * 10 * 10^-3 ]
= ln ( 12/52 ) = -1.466337069 = - 0.45032919 * t
∴ t ≈ 3.26 secs ( -1.466337069 / -0.45032919 )
Answer:
v = 10 m/s
Explanation:
given,
Mass of Mercedes engine = 2000 Kg
Power delivered = 100 kW
angle made with horizontal = 30°
acceleration due to gravity = 10 m/s²
largest speed car can sustain = ?
we know,
Power = Force x velocity
P = F x v
P = mg sinθ x v
P = mg sin 30° x v
P = 0.5 mg x v
v = 10 m/s
hence, the maximum velocity is equal to v = 10 m/s
Frequency with wavelength 1.162m<span> = 344/1.162 = 296.04</span><span>Hz</span>