30 points! Practice making careful observations. Choose something living to observe, either outdoors or indoors. If you’re observing your puppy playing in your backyard, you must not only record the puppy’s actions but the time of day, the weather, the sounds around you, who else is there, etc. All of these things are important, and should anything surprising happen, it becomes very helpful to have all the information.

Aplayground slide is 8.80 ft long and makes an angle of 25.0° with the horizontal. a 63.0-kg child, initially at the top, slides all the way down to the bottom of the slide. (a) choosing the bottom of the slide as the reference configuration, what is the system's potential energy when the child is at the top and at the bottom of the slide? what is the change in potential energy as the child slides from the top to the bottom of the slide? (include the sign of the value in your answer.)