Explanation :
It is given that, the driver accelerates from a stop sign, cruises for 20 s at a constant speed of 60 km/h, and then brakes to come to a stop 40 s after leaving the stop sign.
We know that acceleration is defined as the rate of change of velocity.
Where
dv is the change in velocity, dv = 0 - 60 m/s = -60 m/s
dt is the change in time, dt = 40 s - 30 s = 10 s
So, 
From the graph it is clear that, from 30 s to 40 s the car is decelerating. So, at every second within this time the value of acceleration will be same i.e. 
.
Answer:
7200 kg.m/s
Explanation:
According the law of conservation of linear momentum, the sum of momentum before and after collision are equal.
Using this principle, the sum of initial momentum will be given as p=mv where p is momentum, m is mass and v is velocity
Initial momentum
Mass of whale*initial velocity of whale + mass of seal*initial seal velocity
Since the seal is initially stationary, its velocity is zero. By substitution and taking right direction as positive
Initial momentum will be
1200*6+(280*0)=7200 kg.m/s
Since both initial and final momentum should be equal, hence the final momentum will also be 7200 kg.m/s
Answer:
0.707m
Explanation:
from formula of range i.e R=Usin2Q/g
The answer is having fewer neutrons than protons or electrons.
