With the values you've given, only velocity can be found.
Acceleration is rate of change of velocity
d= 250s
t= 17s
a= d/t
=

= 4.7
If you count the number of seconds between the flash of lightning and the sound of thunder, and then divide by 5, you'll get the distance in miles to the lightning: 5 seconds = 1 mile, 15 seconds = 3 miles, 0 seconds = very close. Keep in mind that you should be in a safe place while counting.
Protons, electrons, and neutrons. The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge).
I think its a higher frequency
Explanation:
It is given that,
Mass of platinum bar, m = 750 g
Length of the bar, l = 5 cm
Breadth of the bar, b = 4 cm
Width of the bar, h = 1.5 cm
Volume of the bar, 

We need to find the density of the platinum bar. The density of any substance is given by :



So, the density of the platinum bar
. Hence, this is the required solution.