Avertical spring has a spring constant of
100. newtons per meter. when an object is
attached to the bottom of the spring, the spring
changes from its unstretched length of 0.50 meter
to a length of 0.65 meter. the magnitude of the
weight of the attached object is
(1) 1.1 n (3) 50. n
(2) 15 n (4) 65 n

Who was the first scientist to measure speed as distance over time?

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.

Consider a 1000 w iron whose base plate is made of 0.5 cm thick aluminum alloy 2024-t6 (ρ = 2770 kg/m3 and cp = 875 j/kg°c). the base plate has a surface area of 0.03 m2. initially, the iron is in thermal equilibrium with the ambient air at 22°c. assuming 90% of the heat generated in the resistance wires is transferred to the plate, determine the minimum time needed for the plate temperature to reach 200°c.