FOUR USES OF CONCAVE MIRROR:Satellite dishes,headlights of a car, telescopes used for astronomical studies, and shaving mirrors because of there curved and reflective surface.
FIVE USES OF LENSES: Camera lens ,microscopes ,magnifying glass,eyeglasses,projector
Is this science because I am suck at it
Answer:
1 ) Distribution of mass within the ball
2 ) Height of the ramp
Explanation:
Acceleration of a rolling body down an inclined plane is given by the following formula
a = g sinθ / ( 1 + k² / R² )
k is radius of gyration , R is radius of the spherical object ,
when acceleration is more , velocity will also be more .
for objects in which masses are lying in the periphery like in hollow sphere , the value of k²/R² will be high so denominator of the expression will be high so acceleration will be less , hence velocity on reaching the bottom will be less.
On mass of the ball , velocity will not depend .
If height is increased , ball will have acceleration for greater time so velocity will be high.
On radius it will not depend because , radius r and k increases proportionately.
ANSWER
75.65 km/h
EXPLANATION
Given:
• The student's mass, m = 77 kg
,
• The kinetic energy of the student in the car, KE = 1.7 x 10⁴ J
Find:
• The speed read in the speedometer of the car, which is the speed of the student, v (in km/h)
The kinetic energy of an object with mass m, traveling at a speed v, is,
Solving for v,
Replace the known values and solve,
Note that because the kinetic energy is given in Joules - which is equivalent to kg*m²/s², the speed we found is in m/s. Now, knowing that there are 3600 seconds in 1 hour and that 1 km is equivalent to 1000 m, we can convert this to km/s,
Hence, the speedometer reading of the car is 75.65 km/h, rounded to the nearest hundredth.
