Answer:
Explanation:
Kinetic energy= K.E = (1/2) × mv²
K.E = 0.5× 0.8kg× 100m²/s² = 40 N
smartphones break due to forces acting on the material.
force causes material to deform.
material is often brittle and cracks due to a limit on hardness / electricity in screens.
newton's 2nd law states
force = DV / DT
to help phones we must slow down change in momentum to reduce the force
thus we must use some form of damping in the form of a case .
the case is typically able to deform and rubber is elastic converting the kinetic energy to heat as it deforms instead of transferring it through the screen.
therefore the change in velocity occurs over a longer time. therefore the impulse decreases
The direction of the motion is constantly changing during
motion over any closed path, not only circular.
Answer:
Answer (b)
Explanation:
Acceleration is the rate of change of velocity in time, therefore constant acceleration will be changing velocity in direct proportion to time and will have a linear plot on a velocity/time chart. This eliminates answer (d) which has an increasing acceleration in time
answer (a) has a negative slope so the acceleration would be considered negative
answer (c) has zero slope so acceleration is zero and velocity is constant.
answer (b) has the required positive slope and acceleration
