Answer: 4 s
Explanation:
Given
The applied force is 70 N
mass of the rock is 28 kg
initial velocity ![u=25\ m/s](https://tex.z-dn.net/?f=u%3D25%5C%20m%2Fs)
final velocity ![v=15\ m/s](https://tex.z-dn.net/?f=v%3D15%5C%20m%2Fs)
Deceleration provided by force is
![a=-\dfrac{70}{28}=-2.5\ m/s^2](https://tex.z-dn.net/?f=a%3D-%5Cdfrac%7B70%7D%7B28%7D%3D-2.5%5C%20m%2Fs%5E2)
using the equation of motion
![v=u+at\\\Rightarrow 15=25-2.5t\\\Rightarrow 2.5t=10\\\Rightarrow t=4\ s](https://tex.z-dn.net/?f=v%3Du%2Bat%5C%5C%5CRightarrow%2015%3D25-2.5t%5C%5C%5CRightarrow%202.5t%3D10%5C%5C%5CRightarrow%20t%3D4%5C%20s)
Answer:
False
Explanation:
When a driver is impaired the brain will need an extra second or two to wake up, after it does wake up it tends to drift off regularly.
The equation for force is F=ma. Because we have the value of mass (0.42 kg) and the acceleration (14.8 m/s^2), simply plug them into the equation for force to get
![0.42 \times 14.8 = 6.22](https://tex.z-dn.net/?f=0.42%20%5Ctimes%2014.8%20%3D%206.22)
The answer is 6.22 N because newtons are the unit used to measure force.
Answer:
Option (b) is correct.
Explanation:
Elastic collision is defined as a collision where the kinetic energy of the system remains same. Both linear momentum and kinetic energy are conserved in case of an elastic collision.
Inelastic collision is defined as a collision where kinetic energy of the system is not conserved whereas the linear momentum is conserved. This loss of kinetic energy may due to the conversion to thermal energy or sound energy or may be due to the deformation of the materials colliding with each other.
As given in the problem, before the collision, total momentum of the system is
and the kinetic energy is
. After the collision, the total momentum of the system is
, but the kinetic energy is reduced to
. So some amount of kinetic energy is lost during the collision.
Therefor the situation describes an inelastic collision (and it could NOT be elastic).