【单选题】A 2.0-kg ball is moving with a constant speed of 5.0 m/s in a horizontal circle whose diameter is 1.0 m. What is the magnitude of the net force on the ball? A) 0 N B) 20 N C) 40 N D) 50 N E) 100 N
【简答题】Fill in the blank(s) in each sentence with a phrase from the box in its appropriate form. stake a claim, plow into be proportional to tread on attribute ... to, carve out sidle up breathe down sb’ s n...
【简答题】Please write the word with the following meaning. a . g i v i n g a n a p p e a r a n c e o r i m p r e s s i o n d i ff e r e n t f r o m t h e t ru e o n e