Discuss a falling stone stopped by another stone

Aregular polygon has angkes of size 150° each.how many side has the polygon

Assume you measured the mass of the cart to be (500 ± 1) g and the mass of the additional mass you put on the cart to be (500 ± 1) g as well. since the scale you are using in the lab cannot measure objects heavier than 600g you will have to sum up individual pieces and propagate the error. so what would be the mass and the standard error of the cart and the mass

According to the image below, which season is about to begin in the southern hemisphere? a. summer b. autumn c. winter d. spring