6 Two cyclists, A and B, have displacements 0 km and 70 km, respectively. At t=0 they

begin to cycle towards each other with

velocities 15 km h and 20 km h-',

respectively. At the same time, a fly that was

sitting on A starts flying towards B with a

velocity of 30 km h-'. As soon as the fly

reaches B it immediately turns around and

flies towards A, and so on until A and B meet.

(a) What will the displacement of the two

cyclists and the fly be when all three

meet?

(b) What will be the distance travelled by the

fly?

You carry a 7.0-kg bag of groceries 1.2 m above the ground at constant speed across a 2.7m room. how much work do you do on the bag in the process? (a) 157j (b) 0.00j (c) 185j (d) 82j

If a simple machine reduces the strength of a force, what must be increased?

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?