Answer:
150000000000 m
0.0000005 seconds
33.33 ns
Explanation:
Speed of electromagnetic waves through vacuum = 
Echo time = 1000 seconds
Echo time is the time taken to reach the object and come back to the observer
Distance = Speed×Time

Venus is 150000000000 m away from Earth
Time = Distance / Speed

Echo time will be twice the time

The echo time will be 0.0000005 seconds
Difference in time = Difference in distance / Speed

The accuracy by which I will be able to measure the echo time is 33.33 ns
formula for gravitational P.E =mgh
Solution:-mass=3kg height=5metre and gravity=9.8 or 10m/sec² so P.E=mgh , 3×9.8×5=147kgm²/sec²
Usually, it increases the solubility in water.
Answer:
Initial velocity, U = 4.5m/s
Explanation:
Given the following data;
Final velocity, v = 12m/s
Time, t = 5 seconds
Acceleration, a = 1.5m/s²
To find the initial velocity, we would use the first equation of motion.
Where;
V is the final velocity.
U is the initial velocity.
a is the acceleration.
t is the time measured in seconds.
Substituting into the equation, we have;
12 = U + 1.5*5
12 = U + 7.5
U = 12 - 7.5
Initial velocity, U = 4.5m/s