Physics
Improve your experience by picking them
A kid's knees are initially on the ground (like in a kneeling position). Upon hopping straight from this state, the kid can reach a height of about 20 cm. While making the hop, his body rises a distance of 16 cm from the knees up. Assume that this is true for his entire body as well. Solve for the force F that the ground exerts on the kid during the hop. Express this in terms of the kid's weight, w.
In a warehouse, a 30.0-kg wooden crate is placed on a sturdy table. A 20.0-kg metal box is then placed on top of the wooden crate as shown. Determine the normal force that the table exerts on the wooden crate and the normal force that the wooden crate exerts on the metal box.
A 90-kg woman steps onto an aluminum rod with a radius of 𝑅=20 cm and a length 𝐿, which stands firmly on a concrete floor. The aluminum atoms in the rod are normally 2.5 × 10-10 meters apart. By what distance must this interatomic spacing change to produce the normal force required to support the woman? The Young's modulus 𝐸 for aluminum is 70×109 N/m270 \times 10^{9} \mathrm{~N} / \mathrm{m}^{2}70×109 N/m2