Answer:
2.06 m/s
Explanation:
From the law of conservation of linear momentum, the sum of momentum before and after collision are equal. Considering this case where we have frictionless surface, no momentum is lost in the process.
Momentum before collision
Momentum is given by p=mv where m and v represent mass. The initial sum of momentum will be 9v+(27*0.5)=9v+13.5
Momentum after collision
The momentum after collision will be given by (9+27)*0.9=32.4
Relating the two then 9v+13.5=32.4
9v=18.5
V=2.055555555555555555555555555555555555555 m/s
Rounded off, v is approximately 2.06 m/s
Answer:
A kilowatt (kW) is a unit of power.
Explanation:
The power of an object is given by :
Here,
E is the energy required
t is time
The SI unit of power is Watts and the SI unit of energy is Joule. the commercial unit of energy is kilowatt per hour.
Option (1) : A kilojoule (kJ) is a unit of power is incorrect.
Option (2) : A gigawatt (GW) is a unit of energy is incorrect.
Option (3) : A watt (W) is a unit of energy is incorrect.
Option (4) : A kilowatt x hour per year (kWh/yr) is a unit of energy is incorrect.
Option (4) : A kilowatt (kW) is a unit of power is correct.
Hence, the correct option is (d).
ΔS= nΔHvap/T,
Where, ΔS = Change in entropy, n = moles of water = 39.3/18 = 2.188 moles, ΔHvap = 40.67kJ/mol = 40670 J/mol, T = Temperature (K) = 100+272.15 = 373.15 K
Therefore,
ΔS = (2.188*40670)/373.15 = 237.96 J/K
Answer:
(a)F= 3.83 * 10^3 N
(b)Altitude=8.20 * 10^5 m
Explanation:
On the launchpad weight = gravitational force between earth and satellite.
W = GMm/R²
where R is the earth radius.
Re-arranging:
WR² / GM = m
m = 4900 * (6.3 * 10^6)² / (6.67 * 10^-11 * 5.97 * 10^24) = 488 kg
The centripetal force (Fc) needed to keep the satellite moving in a circular orbit of radius (r) is:
Fc = mω²r
where ω is the angular velocity in radians/second. The satellite completes 1 revolution, which is 2π radians, in 1.667 hours.
ω = 2π / (1.667 * 60 * 60) = 1.05 * 10^-3 rad/s
When the satellite is in orbit at a distance (r) from the CENTRE of the earth, Fc is provided by the gravitational force between the earth and the satellite:
Fc = GMm/r²
mω²r = GMm / r²
ω²r = GM / r²
r³ = GM/ω² = (6.67 * 10^-11 * 5.97 * 10^24) / (1.05 * 10^-3)²
r³ = 3.612 * 10^20
r = 7.12 * 10^6 m
(a)
F = GMm/r²
F=(6.67 * 10^-11 * 5.97 * 10^24 * 488) / (7.12 * 10^6 )²
F= 3.83 * 10^3 N
(b) Altitude = r - R = (7.12 * 10^6) - (6.3 * 10^6) = 8.20 * 10^5 m
Answer: B) 30 km/h
Explanation:
The speed of Ben and Jerry on their way to the store is given by
where
d is the distance they covered
t is the time they took
From the graph, we see that Ben and Jerry travelled for a distance of d=60 km in a time of t=2 h, so their speed is
