Answer:
A) v_average = - 10 km / h, B) v = 1.6 m / s, v = 17.6 m / s
Explanation:
A) the average speed is the average speed of a body, if we assume that the direction of going up the hill is positive
v₁ = 40 km / h
v₂ = - 60 km / h
the average speed is
v_average = 
v_average = ( 40 - 60)/2
v_average = - 10 km / h
B) in this case they indicate the acceleration a = 3.2 m / s² and the velocity vo = 9.6 m / s
i) the speed for 2.5 s above
v = v₀ + a t
as the time is earlier
t = - 2.5 s
we substitute
v = 9.6 - 3.2 2.5
v = 1.6 m / s
ii) the velocity for a subsequent time of 2.5 s
t = 2.5 s
we substitute
v = 9.6 + 3.2 2.5
v = 17.6 m / s
not too sure on this one maybe to locate objects under water, to diagnose problems, to treat medical ailments
Answer:
b Use a balance to determine the mass of the car. Use a motion sensor to measure the speed of the car at a time of 0s and at time of 5s .
Explanation:
The right way to measure the net force on the car is take the measurement of its mass then find the speed of the car within the time 0s to 5s.
This is because the net force acting on car is given as;
Force = mass x acceleration
By using the balance, the mass is determine
Acceleration is the rate of change of velocity with time.
Acceleration = 
v is the final velocity
u is the initial velocity
t is the time taken
Now,
Force = mass x
Electric field is defined as force per unit charge.
So it is given by
now we can find electric field by
So field strength is 0.75 N/C.
