Answer:
The false statement is in option 'd': The center of mass of an object must lie within the object.
Explanation:
Center of mass is a theoretical point in a system of particles where the whole mass of the system is assumed to be concentrated.
Mathematically the position vector of center of mass is defined as
where,
is the position vector of the mass dm.
As we can see for homogenous symmetrical objects such as a sphere,cube,disc the center of mass is located at the centroid of the shapes itself but in many shapes it is located outside the body also.
Examples of shapes in which center of mass is located outside the body:
1) Horseshoe shaped body.
2) A thin ring.
In many cases we can make shapes of bodies whose center of mass lies outside the body.
Answer:
Explanation:
The sandpaper block did not move because the forces of friction and gravity were balanced.
Answer:
Explanation:
let force exerted by engine be F.Net force =( F-400)N, applying newton law
F-400 = 1.5 x 10³x18 =27000 ,
F = 27400 N.
velocity after 12 s = 0 + 18 x 12 = 216 m/s
Average velocity = (0 + 216 )/2 = 108 m/s
Average power = force x average velocity = 27400 x 108 = 29.6 10⁵ W .⁶
b) At 12 s , velocity = 216 m/s
Instantaneous power = velocity x force = 216 x 27400 = 59.2 x 10⁶ W.
Answer:
The lethal voltage for the electrician under those conditions is 126.5 V.
Explanation:
To discover what is the lethal voltage to the electrician we need to find out what is the voltage that produces 55 mA = 0.055 A when across a resistance of 2300 Ohms (Electrician's body resistancy). For that we'll use Ohm's Law wich is expressed by the following equation:
V = i*R
Where V is the voltage we want to find out, i is the current wich is lethal to the electrician and R is his body resistance. By applying the given values we have:
V = 0.055*2300 = 126.5 V.
The lethal voltage for the electrician under those conditions is 126.5 V.
Answer:
Subducting convergent boundary
Explanation:
Generally, volcanoes occurs in both divergent and convergent boundaries. But the convergent boundary it occurs is usually associated with subduction.
Divergent boundary, plates move away from each other creating a new crust in the process. The diverging plates creates the space for magma to be squeezed through cracks and fissures. The magma's erupt to form volcanoes. In the Atlantic ocean the spreading of the plates causes an upwelling of magma through the crest of the Atlantic ridges. New oceanic crust are formed through this process. Sometimes the magma eruption forms volcanoes that are higher than the sea level.
Convergent boundary , plates collides with each other . But in the case of volcanoes existence , the collision should be between a denser plate(oceanic plates) and a less dense plates(continental plates) so that subduction can take place. The subducted plates (oceanic plates) creates trenches and get expose to high temperature and pressure as it sinks toward the mantle. The upper mantle rocks melts and migrate to the earth surface forming volcanoes . Over 75% of the volcanoes occur along the pacific basin where convergent boundary is dominant. Pacific ring of fire has one of the most number of volcanoes.
