A) What Is the Watermelon S Mass at the Surface of the Earth?

Physics 111 HW6 assigned 16 February 2011

FMA-G-01. At the surface of Jupiter’s moon Io, the acceleration due to gravity is g = 1.81 m/s2. A watermelon weighs 44.0 N at the surface of the Earth. a) What is the watermelon’s mass at the surface of the Earth? b) What is its mass and weight on the surface of Io?

FMA-GN-02. Two crates, A and B, sit at rest side-by-side on a frictionless horizontal surface as shown in the figure at right. The crates have masses mA and mB. A horizontal force F is applied to crate A and the two crates move off to the right. a) Draw clearly-labeled free-body diagrams for crate A and crate B. b) If the magnitude of the force F is less than the total weight of the two crates, will it cause the crates to move? Explain.

FMA-GT-03. An adventurous archaeologist crosses between two rock cliffs by slowly going hand-over-hand along a rope stretched between the cliffs. He stops to rest at the middle of the rope (see figure). The rope will break if the tension in it exceeds 25,000 N, and our hero’s mass is 90.0 kg. a) If the angle θ is 10.0o, find the tension in the rope. b) What is the smallest value the angle θ can have if the rope is not to break?

FMA-GNT-04. Two blocks, each with weight w, are held in place on a frictionless incline (see figure at right). In terms of w and the angle α of the incline, calculate the tension in a) the rope connecting the blocks; b) the rope that connects block A to the wall. c) Interpret your answers for the cases α = 0 and α = 90o.

FMA-GT-05. A hammer is hanging by a light rope from the ceiling of a bus. The ceiling of the bus is parallel to the roadway. The bus is travelling in a straight line on a horizontal street. You observe that the hammer hangs at rest with respect to the bus when the angle between the rope and the ceiling of the bus is 74o. What is the acceleration of the bus?

FMA-GNT-06. Two blocks connected by a cord passing over a small, frictionless pulley rest on frictionless planes (see figure at right). a) Which way will the system move when the blocks are released from rest? b) What is the acceleration of the blocks?

(over) c) What is the tension in the cord?

FMA-GT-07. Two ropes are connected to a steel cable that supports a hanging weight as shown in the figure at right. a) Which of the two ropes will experience a greater force of tension? b) If the maximum tension either rope can sustain without breaking is 5000 N, determine the maximum value of the hanging weight that these ropes can safely support. You can ignore the weight of the ropes and the steel cable.

FMA-GT-16. (toughie?) Masses of 2.0 kg, 3.0 kg, and 4.0 kg are suspended by strings S1, S2, and S3, as shown in figure at right. The whole thing is to be given an upward 2 acceleration of 10 m/s by pulling upwards on S1. Find the tensions in each of the three strings.

(over)