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750 g of hot curry at 80⁰C cools down to 25⁰C after 1 hour left in the kitchen. If the specific heat of the soup is 3.67kJkg∘C, how much energy does the curry release into the kitchen?
A piece of nylon cloth is used to clean the lenses of a pair of glasses. In doing so, which becomes positively charged? Negatively charged? Assume that the lenses are made of glass.
When a rabbit fur is rubbed with a acetate fiber, the fur acquires a change of magnitude 2.23nC.
a. Did the rabbit fur gain or lose electrons?
b. How many electrons were transferred during the process?
c. What is the change in mass of the rabbit fur?
d. What is the change in mass of the acetate fiber?
A paper is rubbed with a wood and the fur acquires a charge of magnitude 5.26nC.
a. Did the paper gain or lose electrons?
b. How many electrons were transferred during the process?
c. What is the change in the mass of the paper?
d. What is the change in the mass of the wood?
In the process of rubbing the lenses of the eyeglasses, 6.28x1010 electrons were transferred.
a. What is the charge of the lenses and the nylon cloth?
b. What is the change in their masses?
An object accelerates at 2.2 m/s2 for 3.0 seconds. If the final velocity is 15m/s what was the initial velocity?
If the torque required to loosen a nut that holds a wheel on a car has a magnitude of 58 N*m, what force
must be exerted at the end of a 35 cm lug wrench to loosen the nut when the angle of the wrench is 560?
A boy who weighs 800 N and his 475 N little sister are 3.5 meters apart from each other on a balanced see-
saw.
a) What is the mass of the little sister?
b) How far away is the little sister sitting from the center of the see-saw?
A wave is modeled by the wave function.
y(x,t)= (0.30m)sin[2pi/4.50m(x-18.00m/st)].
What are the amplitude,wavelength,wave speed, period, and frequency of the wave?
A goat and a dog are in a road race. The goat moves the entire 1000m at the speed of 0.2m/s. The dog runs the first 200m at 2m/s, stops to rest for 45minutes and then continues the race to finish the last 800m with an average speed of 3m/s.
