With a half life of 28.8 years, how long will it take 1g of strontium-90 to decay to 250 mg

Technician a says after tire service work tires and wheels must be in a state of static and dynamic balance in order to avoid vibration in service. technician b says tires and wheels are balanced at the factory and do not need further balancing. who is correct?

What are the countries in south asia?

Environmental science jobs are expected to grow by how much between now and 2016? a) 5% b) 15% c) 25% d) 100%