<span>1) at rest his
weight is 840 N
=> 840N = mass * g => mass = 840 N / g = 840 N / 9.8 m/s^2 = 85.7 kg
2) as the elevator rises, his weight increases to 1050 N,
The reading of the scale is the norma force of it over the body of the person.
And the equation for the force is: Net force = mass * acceleration = normal force - weight at rest
=> mass * acceleration = 1050 N - 840 N = 210 N
acceleration = 210 N / mass = 210 N / 85.7 kg = 2.45 m/s^2 (upward)
3) when the elevator slows to a stop at the 10th
floor, his weight drops to 588 N
=> mass * acceleration = 588 N - 840 N = - 252 N
=> acceleration = - 252 N / 85.71 kg = - 2.94 m / s^2 (downward)
Answer:
Acceleration at the beginning of the trip 2.45 m/s^2 upward
Acceleration at the end of the trip 2.94 m/s^2 downward
</span>
Measuring the Volume of Solids. The volume of solids is expressed in cubic measurements, such as cubic centimeter or cubic meter.
Answer:
Beryllium
Beryllium is an alkaline metallic element that is highly toxic. It is known for its sugary sweet taste and some of its common uses are in X-rays and fluorescent lights.
Beryllium : A very thorough and technical site about this mineral.
Chromite
Chromite is the ore of chromium and is a very hard metal, and diamond is the only thing harder. This hardness is what allows a chrome finish to take a high polish.
Chromite : This site talks about its history and characteristics.
Cobalt
Cobalt is famous for the incredible blue color it imparts to glass and pigment. It has been found in meteorites and is used in invisible ink. It is a brittle metal and resembles iron.
Cobalt : This site has photos, video, charts and physical and atomic descriptions.
Columbite-tantalite
Columbite-tantalite group is a mineral used widely in technology. Electronics, automotive systems and health products like the pacemaker need this mineral to operate. It is mined in Africa and has earned the name of Coltan over the last few years.
Columbite-tantalite : Information about its role in the world under the name 'Coltan'.
Copper
Copper is a common metal throughout the world. It is used for currency, jewelry, plumbing and to conduct electricity. It is a soft, orange-red metal.
Copper : This site talks about its properties, uses and makeup.
Explanation:
Hope that helps :)
Distance is 50 km
Displacement is 10 km
<u>Explanation:</u>
Given:
Distance toward south, x = 25 km
Distance towards west, y = 10 km
Distance towards north, z = 15 km
(a) Total distance, D = ?
Total distance, D = x + y + z
D = 25 + 10 + 15
D = 50km
(b) Displacement, d = ?
Displacement = final position - initial position
= 10 - 0 km
= 10km
Answer:
The ball stops instantaneously at the topmost point of the motion.
Explanation:
Assume we have thrown a ball up in the air. For that we have given a force on the ball and it acquires an initial velocity in the upward direction.
The forces that resist the motion of the ball in the upward direction are the force of gravity and air resistance. The ball will instantaneously come to rest when the velocity of the ball reduces to zero.
The two forces acting in the downward direction reduces its speed continuously and it becomes zero at the topmost point.
