a block of steel weighs more than a block of wood. which one has a greater mass?...more questions in details.?

Question

1. you have a box of sand and a can of water. each has a mass of 1kg. which weighs more?

2. on earth, an astronaut weighs 60kg. how much will she weigh on the moon?

3. the gravity on jupiter is 2 1/2 times greater that of the earth. how much would the 60-kg astronaut weigh if she could land on jupiter? how much mass would she have?

4. what must airplanes and rockets do to fly through the air?

Answer 1

Mass is constant, weight is a variable that depends on the gravity field. To keep things easy under a gravity acceleration of 1 G (9.8 m/sec or 32 ft/sec at sea level) mass = weight.

1. Weight of 1 kg under 1G = Weight of 1 kg under 1G.
The mass of the sand and the water are different, but a kilogram is a standard; so both weigh the same under a 1G field.
2. Lunar gravity is 1/6 that of earth gravity so a 60 kg astronaut on earth would only weigh 10 kg on the moon. However, he would still have a MASS of 60 kg and if he jumped at another astronaut that person would have to brace against at least 60kg of force or he will fall.
3. If the gravity is 2.5 X 1G then the weight is 2.5 X weight so your astronaut on Jupiter would weigh 150 kg. However, he would still have a mass of 60 kg and in as in the same example as before if he jumped at an astronaut the astronaut would have to brace against only 60 kg of force, not 150 kg.
4. Airplanes and rockets must push against the force of gravity and the force of the air to travel. If an airplane travels at less than 9.8 m/sec it will fall, a rocket at that speed will simply burn on the pad.

Mass is the function of the volume of the person or object and unless you crush it the mass is the same; but, if you crush it the mass remains constant because now the object’s density has increased so the mass still remains the same. The only way to decrease the mass is to physically remove something from it.

The weight is dependent on the gravity field, on earth we leave under a 1 G field, and the difference between the gravity field in Death Valley (the lowest place in the US) and inside Denver (the mile high city) is so small that it is ignored. The person in Denver gains a few fractions of a pound if they move to Death Valley, but we don’t count that very often. If that person went to the moon with 1/6th of 1G then their weight would be only 1/6th, however their mass would remain the same.

Gravity is just one force and it is a downward pointing force, always aimed at the core of the earth. Mass undergoes a lot of other forces that try to pull or push it. The mass has to be able to support itself against the 1 G field, but to go forward it only needs to overcome the force of inertia and the force of its own mass. 9.8 m/sec = 35.28 kph; few animals can move that fast to just walk or crawl, they only need to have a body that can withstand a 1 G field. Rockets and airplanes need to have an upward vector that huge to escape the pull of gravity. Planes can’t go that fast, so they can’t leave the earth unless they are jets. Rockets need time to build up to that huge speed and actually require a speed of at least 25,000 mph (11175.98 kph) to escape the pull of the earth and break earth orbit.

Answer 2

Basic question: if the objects are being weighed under the same conditions, their weight is proportional to their mass. Therefore, the block of steel, which weighs more than the block of wood and assuming that both blocks are weighed at the same location, would also have the greater mass.

1. The mass of the two objects is the same, so they would weigh the same at the same location.

2. More precisely from a philosophical point of view, the astronaut weighs 60 * 9.8 newtons or about 588 newtons. She may weigh slightly more or less, depending on the altitude, latitude, and, to a very slight extent, the proximity and size of any local particularly dense rock formations. The kilogram is more properly a unit of mass. The astronaut would weigh about the same as a 10 kg mass would on earth.

3. The astronaut would weigh 2 1/2 times more on Jupiter than she would on earth, which wold be the same as a 150 kg mass weighed on earth. Her mass would still be 60 kg though.

4. Airplanes and rockets must have an upward force applied to them strong enough to counteract the downward gravitational force. Otherwise, they will lose altitude and eventually stop flying.