1. A liquid of mass 250g is heated with an electric heater. Its temperature rises from 30°C to 80°C, the specific heat capacity of the liquid is 2000J/kg°C and the power rating of the heater is 500W. For how long was the heater used? 2. A solid metal of mass 2kg is heated using a heater of power 2kW for 5 minutes. Its final temperature becomes 400°C. Find the initial temperature of the metal. Specific heat capacity of the metal=1J/g°C.

1) 50 seconds 2) 100°C

Explanation:

(Follows formula of Power=Energy/Time)

1) 500W x X = 2000J/kg°C x .25kg x 50°C

X = 50 seconds.

2) 2000W x 300s = 1000J/kg°C x 2kg x X

X = 300

Initial temperature => 400°C-300°C = 100°C

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c) both a and b.

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)