Một vật được ném từ đỉnh tòa nhà cao 20 m so với mặt đất với vận tốc ban đầu 12 m / s hợp với phương ngang một góc O = 30 ° . Tính khoảng cách từ vị trí vật chạm đất đến chân tòa nhà ( gốc O ) . Lưu ý Sử dụng hệ trục Oxy được chọn như hình 2. Bỏ qua lực cản không khí

Which sound characteristic is not affected by the relative motion of an object

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.

Asled is being held at rest on a slope that makes an angle θ with the horizontal. after the sled is released, it slidesa distance d1 down the slope and then covers the distance d2 alongthe horizontal terrain before stopping. find the coefficient ofkinetic friction μk between the sled and the ground, assumingthat it is constant throughout the trip. find the coefficient of kinetic frictionμk. express your answer in terms of someor all of the variables d1, d2, and θ.