Which of the following is an idea that robert hutchings goddard introduced in his "further developments" to his research "a method of reaching extreme altitudes"?

a. lunar energy

b. nuclear energy

c. solar energy

d. wave energy

Earth's polar ice caps contain about 2.3 * 1019 kg of ice. This mass contributes essentially nothing to the moment of inertia of the earth because it is located at the poles, close to the axis of rotation.

David keeps harping over any problem that he comes across at work. He goes over the details regarding the problem repeatedly. In the end, David is confused about the problem, and is therefore unable to find a solution for the problem.

The increase in the volume of 10cm³ of mecury when the temperature rises by 100°C is 0.8 cm³. What is the cubic expansivity of mecury?

A person carries a plank of wood 2.00 m long with one hand pushing down on it at one end with a force f1 and the other hand holding it up at. 500 m from the end of the plank with force f2. if the plank has a mass of 20.

A block of mass 3 kg, which has an initial speed of 4 m/s at time t = 0, slides on a horizontal surface. Find the magnitude of the work that must be done on the block to bring it to rest.

Contrast balanced and unbalanced forces.

A wave will travel only as long as it has energy

a box sliding on a frictionless surface when it suddenly begins to rain heavily. if the downpour of rainfall falls vertically into the box, gradually filling it, what would happen to the speed of the box

Which would fall with a greater acceleration in a vacuum-a leaf or a stone?

A force acts on a 5kg object at rest. How fast will the object accelerate on a frictionless surface? A.) 4 m/s^2 B.) 15 m/s^2 C.) 25 m/s^2 D.) 100 m/s^2