Which of these causes summer in the northern hemisphere? The Sun is closer to Earth during the summer.

The northern hemisphere receives more direct sunlight during the summer.

Earth's northern axis is tilted away from the Sun during the summer.

The North Pole is tilted away from the Sun during the summer.

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.)