The foundations that support a building are long concrete cylinders that are pointed at one end. A pile-driver is a machine that forces the pointed concrete cylinders into the ground. Fig. 2.1 shows a pile-driver. [Figure 2.1] A heavy block of mass 2.9 × 10⁴ kg is lifted into the air then dropped onto the top of a concrete cylinder. This forces the cylinder into the ground.

1. (a)Fig. 2.2 shows the heavy block. The block is 2.0 m tall and has a cross-sectional area of 1.8 m². Calculate the density of the material used to make the block.[2]
2. (b)(i)The pile-driver lifts the block from the top of a concrete cylinder, through a height of 0.80 m. The gravitational field strength g is 10 N/kg. Calculate the gravitational potential energy gained by the block.[2]
3. (b)(ii)The block is then dropped from rest onto the top of the concrete cylinder. Calculate the speed of the block just before it hits the concrete cylinder.[3]

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