The centripetal acceleration is given by

where v is the tangential speed and r the radius of the circular orbit.
For the car in this problem,

and r=40 m, so we can re-arrange the previous equation to find the velocity of the car:
Answer:
a = 0.8 m/s^2
Explanation:
Force equation: F = ma
F = ma -> a = F/m = 2.8*10^3 N / 3.5*10^3 kg = 0.8 m/s^2
0.4 N-s is the "impulse" acted on the "beach ball".
Option: C
Explanation:
Given that,
Mass of the "beach ball" is 0.1 kg.
The speed of the ball hits is 4 m/s.
We know that,
Whenever an object is collide with other object then an impulse is acted on object, this "impulse" causes "change in momentum".
Impulse acted on the beach ball is "mass" times "velocity".
Impulse = mass × velocity
Impulse = 0.1 × 4
Impulse = 0.4 kg m/s
Impulse = 0.4 N-s
Therefore, the "impulse" acted on the ball is 0.4 N-s.
Answer:
intensity of sound at level of microphone is 0.00139 W / m 2
sound intensity level at position of micro phone is 91.456 dB
EXPLANATION:
Given data:
power of sound P = 31 W
distance betwen microphone & speaker is 42 m
a) intensity of sound at microphone is calculated as


= 0.00139 W / m 2
b) sound intensity level at position of micro phone is

where I_o id reference sound intensity and taken as

= 91.456 dB
As per the question there are two physical quantities i.e scalar quantity and vector quantity.
A scalar is a physical quantity which requires only magnitude.It does not require any direction for it's complete specification.For instance we may take distance travelled,speed etc.
Unlike a scalar quantity,a vector quantity requires both magnitude as well as direction for it's complete specifications.For instance we may take displacement which is the shortest distance between two points,the velocity which is the speed in a given direction.
Hence a vector and scalar is differentiated by direction.
As per the question,the correct option will be the third option i.e C.
Carlita is right.As per her, both vector and scalar have magnitude,but only vectors have direction which is also true.