As momentum, p = m x v = 0.2 x 400 = 2/10 x 400 = 80 kg m/s

More force is needed to stop a cricket ball (which has more mass) and less force is needed to stop a tennis ball (which has less mass). The force required to stop a moving ball is proportional to mass (m) ...

The central vacuole of some plant cells can occupy 50-90% of the cell volume.

Chloroplasts are involved in trapping light energy for photosynthesis. Leucoplast are colourless plastids that stores, material such as starch, oil and protein granules. Chromplasts are the coloured plastids that imparts colours to the plant.

Chloroplasts are pigment containing plastids. They are important for photosynthesis in plants. They contain various yellow or orange pigments in addition to chlorophyll.