The apple is thrown vertically upwards with speed 3.0 m s−1. The knife is thrown with speed 8.0 m s−1.

When the knife and apple collide, they are both at the highest points of their trajectories.

At what angle from the horizontal, θ, was the knife thrown?

(You may ignore air resistance. Take the acceleration due to gravity to be 10 m s−2.)

The gravitational force between two objects is 1600 and what will be the gravitational force between the objects if the distance between them doubles?

The built in flash in a compact camera is usally capable of giving correct exsposure for distance up to how many meters?

In an old-fashioned amusement park ride, passengers stand inside a 3.0-m-tall, 5.0-m-diameter hollow steel cylinder with their backs against the wall. the cylinder begins to rotate about a vertical axis. then the floor on which the passengers are standing suddenly drops away! if all goes well, the passengers will “stick” to the wall and not slide. clothing has a static coefficient of friction against steel in the range 0.60 to 1.0 and a kinetic coefficient in the range 0.40 to 0.70. part a what is the minimum rotational frequency, in rpm, for which the ride is safe? express your answer using two significant figures. f f = rpm