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a student wants to study the effect of adding thermal energy to a system. which of the following experiments should the student perform?

heat water and record its change in temperature with time.
freeze water and record its change in temperature with time.
close a circuit by adding a paperclip and record if the blub glows.
close a circuit by adding a wooden piece and record if the bulb glows.

5g of ammonium nitrate was dissolved in 60g of water in an insulated container. the temperature at the start of the reaction was 23.0°c and at the end it was 19.0°c. calculate the energy absorbed by the reaction.

Aspring has a relaxed length of 33 cm (0.33 m) and its spring stiffness is 6 n/m. you glue a 76 gram block (0.076 kg) to the top of the spring, and push the block down, compressing the spring so its total length is 15 cm. you make sure the block is at rest, then at time t=0 you quickly move your hand away. the block begins to move upward, because the upward force on the block by the spring is greater than the downward force on the block by the earth. calculate y vs. time for the block during a 0.09-second interval after you release the block, by applying the momentum principle in three steps each of 0.03-second duration.

You walk 45 m to the north, then turn 90° to your right and walk another 45 m how far are you from where you originally started? a.45 m b.41 m c.85 m d.64 m