Question

factors affecting an objects energy
in a science lab, tina and carlos held a small cart at the top of a ramp. they used the mass of the cart and the height of the ramp to determine the gravitational potential energy of the cart before it was let go. then they let go of the cart and observed its motion. they used the speed of the cart and the time it took to travel to the bottom of the ramp to determine its kinetic energy as it reached the bottom of the ramp.
tina and carlos changed the height of the ramp and the mass of the cart in each experiment. they changed the height of the ramp from 12 cm to 6 cm.

• in experiment 1, the carts mass is 150 g.
• in experiment 2, they added a mass of 30g to the cart.

the students recorded their data in the table.
table 1: height and mass influence on energy type
experiment 1
experiment 2

1. how do the gravitational potential energy and the kinetic energy change as the cart rolls down the ramp?

science coach
identify where
kinetic energy is
transformed into potential
energy or vice versa as the cart
rolls down the ramp.
f both gravitational potential energy and kinetic energy increase.
g both gravitational potential energy and kinetic energy decrease.
h gravitational potential energy increases and kinetic energy decreases.
i gravitational potential energy decreases and kinetic energy increases.

1. how does the activity performed by tina and carlos qualify as an experiment instead of another type of investigation?

science coach
think about the
difference between an
experiment and other types
of scientific investigations. then
relate the definition of an
experiment to this activity.
f they made observations about events.
g they controlled variables and recorded data.
h they drew conclusions about scientific ideas.
i they studied a single object under constant conditions.

Explanation:

Question 4

• Gravitational potential energy (\(U = mgh\)) depends on height (\(h\)). As the cart rolls down, \(h\) decreases, so gravitational potential energy decreases.
• Kinetic energy (\(K=\frac{1}{2}mv^{2}\)). As the cart accelerates down the ramp, its speed (\(v\)) increases, so kinetic energy increases.
• Total mechanical energy (\(E = U + K\)) is conserved (assuming no non - conservative forces like friction, as per the data in the table where total energy is constant).

• An experiment is characterized by controlling variables (in this case, height of the ramp and mass of the cart) and recording data (gravitational potential energy, kinetic energy, total energy).
• Making observations (F) is part of many scientific activities, not unique to experiments. Drawing conclusions (H) is a later step after data collection. Studying a single object under constant conditions (I) does not describe the variable - changing nature of an experiment.

Answer:

I. Gravitational potential energy decreases and kinetic energy increases.

Question 5