Julie wanted to know if adding calcium fertilizer to tomato plants will prevent a disease of tomato plants called blossom-end rot. she used 10 tomato plants. she put 5 plants in a sunny part of the garden and gave each one calcium fertilizer once a week. she placed the other 5 plants in a shady part of the garden and gave them calcium fertilizer twice a week—she thought that since they were in the shade they might need more fertilizer. she then observed the 10 plants for 3 months to see if the fertilizer prevent blossom-end rot. identify and explain one weakness in julie's experimental design.

Two manned satellites approaching one another at a relative speed of 0.550 m/s intend to dock. the first has a mass of 2.50 ✕ 103 kg, and the second a mass of 7.50 ✕ 103 kg. assume that the positive direction is directed from the second satellite towards the first satellite. (a) calculate the final velocity after docking, in the frame of reference in which the first satellite was originally at rest.(b) what is the loss of kinetic energy in this inelastic collision? (c) repeat both parts, in the frame of reference in which the second satellite was originally at rest. final velocity(d) loss of kinetic energy = ?