Atomic and Nuclear Physics Answers

Cobalt-60 has a half-life of approximately 5 years. If there was one microgram present in a sample originally, how many atoms would have decayed after 20 years?

A 0.15kg tumor is treated with α

α particles. There are 2×10

12

2×1012 particles reaching the tumor every second, each having energy 3×10

−15

3×10−15J. What is the absorbed dose given to the tumor

What absorbed dose of α

α- particles(Q=20) causes as much biological damage as a 100Gy dose of protons(Q=10).

A stone is thrown downward at 30 m/s. What is its speed, [2]

a)after 1s b) after 2s

What is the coefficient of kinetic friction between the 100 N and 39 ⁰

A ball of mass 5 kg is dropped from a height of 1.4 m (from the ground). ) onto a massless spring (a spring with a length balance of 0.5 m). The ball compresses the spring a distance of 0.29 m while at rest. Calculation springs.

As a sled moves across a flat snow-covered field at constant velocity, is any work done?

How does air resistance enter into the picture?

What is the coefficient of kinetic friction between the 100 N and 39 ⁰

How long will it take for a 10-mCi (370 MBq) sample of 32P(t1/2 ¼ 14.3 days) and a 100-mCi(3.7 GBq)sampleof67Ga(t1/2 ¼ 3.2 days) topossess the same activity?

A 60-kg patient about to have a brain scan is injected with 0.02 Ci of the radionuclide Technetium-99. Technetium-99 decays to the ground state with a half-life of 6.0 hours. The Technetium-99 nucleus decays by emitting a 143-keV photon. Assume that half of these photons escape the body without interacting. What biological equivalent dose does the patient receive? The relative biological effectiveness (RBE) for these photons is 0.97. Assume that all of the Technetium-99 decays while in the body